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Guide
When Your AC Unit Starts Leaking: Quick Signs and Causes
A leaking AC unit is a common HVAC problem, especially during hot Kansas summers. Water pooling indoors or dripping from the ceiling can quickly escalate from an annoyance to a costly repair.
Quick troubleshooting for a leaking AC unit:
- Turn off your AC immediately to prevent further damage
- Check for water puddles around the indoor unit (indicates water leak)
- Listen for hissing sounds near refrigerant lines (indicates refrigerant leak)
- Look for ice buildup on evaporator coils (sign of airflow problems)
- Inspect your air filter - if dirty, replace it immediately
- Call a professional if you suspect refrigerant leak or see significant water damage
The good news is many leaks have simple, DIY-friendly causes. A clogged condensate drain line is the most common culprit for water leaks, followed by dirty air filters that restrict airflow and freeze evaporator coils.
However, not all AC leaks are the same. Water leaks are often DIY-friendly, but refrigerant leaks require a different approach, posing health risks that demand professional attention.
This guide will help you identify your leak, understand its cause, and decide whether to DIY the fix or call an expert.
Is It Water or Refrigerant? How to Identify Your AC Leak
If you find a leaking AC unit, act quickly. First, identify if it's water or refrigerant. This determines your next steps and ensures your family's safety.
Turn off your AC immediately. Running a leaking system makes the problem worse and creates a risk of electrical shorts or fires if water is near electrical components. Safety first.
With the system off, you can investigate. Water and refrigerant leaks have distinct signs.
Water Leak Symptoms
Water leaks are more common and usually less serious. Your AC naturally creates water during cooling, which should drain away. A leak means this process has failed.
Puddles of water are the main clue, typically found around the indoor unit or dripping from the ceiling if the unit is in the attic. If you have standing water in your drain pan, see our guide on Fix a Flooded AC Drain Pan in Homes.
A persistent dripping sound, even when the AC is off, often indicates a water leak.
A musty, damp smell suggests mold and mildew are growing in standing water from the leak.
Another sign is increased indoor humidity. A leaking AC can't dehumidify effectively, making your home feel sticky even if it's cool.
Refrigerant Leak Symptoms
Refrigerant leaks are serious and require immediate professional attention. This chemical cools your air, and a leak causes performance issues and health hazards.
Hissing or bubbling sounds are a key sign. Refrigerant escapes under pressure, sounding like air leaking from a tire.
An oily residue on copper refrigerant lines or coils is another clue. The oil is a lubricant mixed with the refrigerant.
A faint, sweet chemical smell can also indicate a refrigerant leak, different from the musty odor of a water leak.
The biggest sign is poor performance. If your AC blows warm air or runs constantly without cooling, low refrigerant is a likely cause. See our guide on AC Blowing Warm Air Fixes for Homeowners for more tips.
Refrigerant leaks can also cause evaporator coils to freeze. When the ice melts, it creates a water leak, masking the true refrigerant problem. Our guide on Troubleshooting AC Refrigerant Leak Signs can help clarify this.
| Symptom Category | Water Leak (Typically) | Refrigerant Leak (Typically) |
|---|---|---|
| Appearance | Puddles, drips, water stains | Oily residue on coils/pipes, ice buildup on evaporator coils |
| Sound | Dripping, gurgling (if drain line is clogged) | Hissing, bubbling, gurgling |
| Smell | Musty, damp, moldy | Sweet, chemical (can be faint or absent) |
| AC Performance | May still cool, but often with increased humidity | Poor cooling, warm air, unit runs constantly but inefficiently |
When in doubt, call a professional. If you see multiple symptoms or are unsure of the leak type, it's safer to get an expert opinion. Your safety and comfort are worth the service call.
Common Causes of a Water-Leaking AC Unit
To understand why your leaking AC unit is leaking water, you need to know how it handles moisture. Your AC pulls warm, humid air over cold evaporator coils, causing moisture to condense, much like on a cold glass.
Normally, this water drips into a condensate pan and flows outside through a drain line. When this system fails, water leaks into your home.
Here are the most common causes of water leaks.
Clogged Condensate Drain Line
A clogged condensate drain line is the #1 cause of a leaking AC unit. This PVC pipe is responsible for most AC water leaks in Kansas homes.
Over time, dirt, debris, algae, and mold can accumulate in the drain line, forming a clog that blocks water flow.
The water then backs up and causes the drain pan to overflow. Fortunately, this is often an easy fix if caught early.
If you're dealing with this issue in the Shawnee area, check out our guide on When AC Drain Line Clogs in Shawnee. For a step-by-step approach to clearing the clog yourself, this resource explains How to clean a clogged AC drain line.
Dirty Air Filter
Surprisingly, a dirty air filter can cause a water leak. A clogged filter leads to a chain of events that results in water on your floor.
When a dirty filter restricts airflow, it prevents warm air from reaching the evaporator coil. This causes the coil to get too cold and freeze solid.
When the ice melts, the sudden rush of water can overwhelm the drain pan, causing it to overflow.
This is why we always recommend checking your air filter first when you find a water leak. Need help with proper filter maintenance? Here's a helpful guide on How to clean an AC filter. If you're in our service area and need professional AC maintenance, we offer AC Services Shawnee KS.
Damaged or Rusted Drain Pan
The condensate drain pan collects moisture from the evaporator coil but can wear out over time due to age and corrosion, especially in older units.
Metal pans can rust, creating cracks or holes that allow water to drip through instead of flowing to the drain line.
Systems have a primary drain pan under the coil and often a secondary drain pan underneath the unit as a backup, especially in attics.
If you notice water dripping through the pan rather than overflowing from the edges, you're likely dealing with a damaged pan that needs replacement.
Broken Condensate Pump
Basement or attic units often use a condensate pump to actively push water outside through the drain line.
A pump can fail due to electrical malfunction, mechanical breakdown, or clogs. A failed pump leads to water overflow and leaks.
Pump issues often involve electrical components and require professional repair. If your unit has a pump and is leaking, contact a service like AC Repair Olathe KS for safe repairs.
Understanding Refrigerant Leaks and Their Dangers
Unlike water leaks, refrigerant leaks are a serious challenge requiring immediate attention. Your AC is a closed-loop system, meaning refrigerant circulates without needing a refill. When it escapes, your comfort and safety are at risk.
The Role and Risks of a Leaking AC Unit with Low Refrigerant
Refrigerant is your AC's heat transfer fluid. It works by changing from liquid to gas, absorbing indoor heat at the evaporator coil and releasing it outside at the condenser coil. This cycle cools your home.
When a leaking AC unit loses refrigerant, it suffers from reduced cooling efficiency and may blow warm air. Low refrigerant can also cause the evaporator coils to freeze solid.
A frozen coil can lead to a water leak when the ice melts, masking the underlying refrigerant issue. If your AC Fan Runs but Compressor Won't Start, a refrigerant leak could be the cause.
Health risks are also a concern. Refrigerant exposure can cause dizziness and breathing difficulties. If you suspect a leak, turn off the AC and ventilate the area.
The most costly risk is compressor damage. The compressor overworks to compensate for low refrigerant, leading to overheating and failure. Catching leaks early can save you from an expensive compressor replacement.
What Causes Refrigerant Leaks?
Refrigerant leaks develop over time. Normal vibrations can loosen connections or create small stress fractures in the refrigerant lines.
Formicary corrosion is another common cause. Household chemicals can react with moisture on copper pipes, creating formic acid that eats tiny pinhole leaks into the metal over time.
The system's seals and valves can also wear out from heat, chemicals, and vibration, becoming brittle and losing their tight seal.
Physical damage from lawnmowers, tree branches, or improper installation can also cause leaks. This damage can contribute to other issues, like Why AC Freezes Up in Hot Summers.
Bottom line: Refrigerant leaks are serious and require a certified HVAC technician to safely diagnose, repair, and recharge your system.
Your Action Plan: DIY Fixes vs. Calling a Professional
When you find a leaking AC unit, you must decide whether to fix it yourself or call a professional. The answer depends on the cause and your comfort level with DIY repairs.
Many water leaks have simple DIY solutions. However, knowing your limits is crucial for safety and to avoid turning a minor repair into a major expense.
Safety always comes first. If you're unsure, call a professional. Also, check your warranty, as some DIY repairs can void it.
Simple DIY Fixes You Can Try
Several common causes of AC water leaks are easy to fix yourself.
Changing your air filter is the easiest fix. A dirty filter restricts airflow, causing the evaporator coil to freeze. When the ice melts, it can overwhelm the drain pan. Replace your filter every 1-3 months for efficiency and to prevent leaks.
Clearing a clogged condensate drain line is another DIY task. Use a wet/dry vacuum on the outdoor end of the pipe to suck out the clog. Alternatively, pour distilled white vinegar down the indoor access point, let it sit for 30 minutes, and then flush with water. Avoid using bleach.
Check your thermostat settings. Ensure it's set to "cool" and the fan is on "auto." A constantly running fan can cause issues with condensation. For more help, see our AC Thermostat Problems Troubleshooting Guide.
Ensure all vents are open. Blocked vents restrict airflow, which can lead to frozen coils. Check that furniture or other items are not blocking any supply or return vents.
When to Call an HVAC Technician
Some AC problems require a professional because they are either too risky for DIY or require specialized tools and training.
- Suspected refrigerant leak: Call a professional immediately. Hissing sounds, chemical smells, or oily residue are red flags. Handling refrigerant is illegal for unlicensed individuals and poses health risks.
- Persistent frozen coils: If coils keep freezing after you've changed the filter and checked airflow, it likely indicates low refrigerant or another serious issue requiring professional diagnosis.
- Electrical issues: Never attempt DIY electrical repairs. If you see flickering lights, trip breakers, or smell burning, turn off the system and call an expert immediately.
- Major component failures: Damaged drain pans, broken condensate pumps, or compressor problems require professional tools and expertise.
- Significant water damage: If the leak has caused major water damage, you'll need professional AC repair and possibly water damage mitigation to prevent mold.
- DIY fixes don't work: If you've tried the simple fixes and the leak persists, it's time for an expert to diagnose a potentially more complex underlying issue.
For expert help in the Kansas City area, contact our team for AC Repair Lenexa KS. We also offer 24/7 AC Repair Overland Park KS for emergencies.
Frequently Asked Questions about Leaking AC Units
Dealing with a leaking AC unit brings up many questions. Here are answers to the most common ones we hear from homeowners in the Kansas City area.
Can I still use my AC if it's leaking water?
No. You should turn your AC off immediately if it's leaking water. Continuing to run it can cause significant problems.
Running a leaking AC leads to costly issues. Water damage can spread quickly to floors, walls, and ceilings, leading to expensive structural repairs. Mold growth can begin within 24-48 hours in standing water, causing musty smells and triggering respiratory issues. There is also an electrical hazard, as water near electrical components can cause short circuits, permanent damage, or even a fire. Running the unit will only make the underlying problem worse.
How can I prevent my AC from leaking in the future?
Most AC leaks are preventable with basic maintenance.
- Regular filter changes are crucial. A clean filter prevents frozen coils. Check your filter monthly and replace it if it's dirty (typically every 1-3 months).
- Annual drain line maintenance is also key. Flushing the line annually removes buildup and prevents clogs, saving you from emergency summer repairs.
- Professional tune-ups allow a technician to spot potential issues like cracks, early leaks, or worn components. Catching problems early prevents expensive emergency repairs.
Our AC Maintenance Plan Guide 2025 outlines what preventive maintenance should include and how it protects your investment.
What are the consequences of ignoring an AC leak?
Ignoring a leaking AC unit will only lead to bigger problems and higher repair bills.
- Water damage can escalate quickly, leading to warped floors, stained ceilings, and damaged drywall.
- Mold and mildew will grow, affecting your home's air quality and potentially causing respiratory issues.
- Electrical problems can occur if water reaches wiring, leading to short circuits and safety hazards.
- Your utility bills will increase as the inefficient system works harder.
- The stress can lead to complete system failure, requiring a full replacement instead of a simple repair.
Keep Your Cool and Your Home Dry
A leaking AC unit can be overwhelming, but with the right knowledge, you can handle it. Quick action is key to preventing a minor issue from becoming a major repair.
The path is straightforward: Identify the leak. Puddles and musty smells suggest a water issue you might fix yourself. Hissing sounds and chemical odors indicate a refrigerant leak that requires a professional.
Water leaks are often caused by a dirty air filter or a clogged drain line. These are simple, DIY-friendly fixes that can save you time and money.
However, know your limits to stay safe and save money. Refrigerant leaks, persistent frozen coils, electrical issues, and major component failures are not DIY jobs and require a certified HVAC technician.
The best way to avoid future leaks is prevention through regular maintenance. Change your filter regularly and schedule annual professional tune-ups to prevent unexpected breakdowns during hot Kansas summers.
At Patriot Heating & AC, we help homeowners across the greater Kansas City area, including Shawnee, Overland Park, Lenexa, Olathe, and Leawood, resolve AC leak emergencies. We are your partners in maintaining a comfortable home year-round.
When you need reliable repair, don't hesitate to reach out. For expert service in the Lenexa area, trust a certified HVAC contractor. Your comfort is worth it.
When Your AC Unit Starts Leaking: Quick Signs and Causes
A leaking AC unit is a common HVAC problem, especially during hot Kansas summers. Water pooling indoors or dripping from the ceiling can quickly escalate from an annoyance to a costly repair.
Quick troubleshooting for a leaking AC unit:
- Turn off your AC immediately to prevent further damage
- Check for water puddles around the indoor unit (indicates water leak)
- Listen for hissing sounds near refrigerant lines (indicates refrigerant leak)
- Look for ice buildup on evaporator coils (sign of airflow problems)
- Inspect your air filter - if dirty, replace it immediately
- Call a professional if you suspect refrigerant leak or see significant water damage
The good news is many leaks have simple, DIY-friendly causes. A clogged condensate drain line is the most common culprit for water leaks, followed by dirty air filters that restrict airflow and freeze evaporator coils.
However, not all AC leaks are the same. Water leaks are often DIY-friendly, but refrigerant leaks require a different approach, posing health risks that demand professional attention.
This guide will help you identify your leak, understand its cause, and decide whether to DIY the fix or call an expert.
Is It Water or Refrigerant? How to Identify Your AC Leak
If you find a leaking AC unit, act quickly. First, identify if it's water or refrigerant. This determines your next steps and ensures your family's safety.
Turn off your AC immediately. Running a leaking system makes the problem worse and creates a risk of electrical shorts or fires if water is near electrical components. Safety first.
With the system off, you can investigate. Water and refrigerant leaks have distinct signs.
Water Leak Symptoms
Water leaks are more common and usually less serious. Your AC naturally creates water during cooling, which should drain away. A leak means this process has failed.
Puddles of water are the main clue, typically found around the indoor unit or dripping from the ceiling if the unit is in the attic. If you have standing water in your drain pan, see our guide on Fix a Flooded AC Drain Pan in Homes.
A persistent dripping sound, even when the AC is off, often indicates a water leak.
A musty, damp smell suggests mold and mildew are growing in standing water from the leak.
Another sign is increased indoor humidity. A leaking AC can't dehumidify effectively, making your home feel sticky even if it's cool.
Refrigerant Leak Symptoms
Refrigerant leaks are serious and require immediate professional attention. This chemical cools your air, and a leak causes performance issues and health hazards.
Hissing or bubbling sounds are a key sign. Refrigerant escapes under pressure, sounding like air leaking from a tire.
An oily residue on copper refrigerant lines or coils is another clue. The oil is a lubricant mixed with the refrigerant.
A faint, sweet chemical smell can also indicate a refrigerant leak, different from the musty odor of a water leak.
The biggest sign is poor performance. If your AC blows warm air or runs constantly without cooling, low refrigerant is a likely cause. See our guide on AC Blowing Warm Air Fixes for Homeowners for more tips.
Refrigerant leaks can also cause evaporator coils to freeze. When the ice melts, it creates a water leak, masking the true refrigerant problem. Our guide on Troubleshooting AC Refrigerant Leak Signs can help clarify this.
| Symptom Category | Water Leak (Typically) | Refrigerant Leak (Typically) |
|---|---|---|
| Appearance | Puddles, drips, water stains | Oily residue on coils/pipes, ice buildup on evaporator coils |
| Sound | Dripping, gurgling (if drain line is clogged) | Hissing, bubbling, gurgling |
| Smell | Musty, damp, moldy | Sweet, chemical (can be faint or absent) |
| AC Performance | May still cool, but often with increased humidity | Poor cooling, warm air, unit runs constantly but inefficiently |
When in doubt, call a professional. If you see multiple symptoms or are unsure of the leak type, it's safer to get an expert opinion. Your safety and comfort are worth the service call.
Common Causes of a Water-Leaking AC Unit
To understand why your leaking AC unit is leaking water, you need to know how it handles moisture. Your AC pulls warm, humid air over cold evaporator coils, causing moisture to condense, much like on a cold glass.
Normally, this water drips into a condensate pan and flows outside through a drain line. When this system fails, water leaks into your home.
Here are the most common causes of water leaks.
Clogged Condensate Drain Line
A clogged condensate drain line is the #1 cause of a leaking AC unit. This PVC pipe is responsible for most AC water leaks in Kansas homes.
Over time, dirt, debris, algae, and mold can accumulate in the drain line, forming a clog that blocks water flow.
The water then backs up and causes the drain pan to overflow. Fortunately, this is often an easy fix if caught early.
If you're dealing with this issue in the Shawnee area, check out our guide on When AC Drain Line Clogs in Shawnee. For a step-by-step approach to clearing the clog yourself, this resource explains How to clean a clogged AC drain line.
Dirty Air Filter
Surprisingly, a dirty air filter can cause a water leak. A clogged filter leads to a chain of events that results in water on your floor.
When a dirty filter restricts airflow, it prevents warm air from reaching the evaporator coil. This causes the coil to get too cold and freeze solid.
When the ice melts, the sudden rush of water can overwhelm the drain pan, causing it to overflow.
This is why we always recommend checking your air filter first when you find a water leak. Need help with proper filter maintenance? Here's a helpful guide on How to clean an AC filter. If you're in our service area and need professional AC maintenance, we offer AC Services Shawnee KS.
Damaged or Rusted Drain Pan
The condensate drain pan collects moisture from the evaporator coil but can wear out over time due to age and corrosion, especially in older units.
Metal pans can rust, creating cracks or holes that allow water to drip through instead of flowing to the drain line.
Systems have a primary drain pan under the coil and often a secondary drain pan underneath the unit as a backup, especially in attics.
If you notice water dripping through the pan rather than overflowing from the edges, you're likely dealing with a damaged pan that needs replacement.
Broken Condensate Pump
Basement or attic units often use a condensate pump to actively push water outside through the drain line.
A pump can fail due to electrical malfunction, mechanical breakdown, or clogs. A failed pump leads to water overflow and leaks.
Pump issues often involve electrical components and require professional repair. If your unit has a pump and is leaking, contact a service like AC Repair Olathe KS for safe repairs.
Understanding Refrigerant Leaks and Their Dangers
Unlike water leaks, refrigerant leaks are a serious challenge requiring immediate attention. Your AC is a closed-loop system, meaning refrigerant circulates without needing a refill. When it escapes, your comfort and safety are at risk.
The Role and Risks of a Leaking AC Unit with Low Refrigerant
Refrigerant is your AC's heat transfer fluid. It works by changing from liquid to gas, absorbing indoor heat at the evaporator coil and releasing it outside at the condenser coil. This cycle cools your home.
When a leaking AC unit loses refrigerant, it suffers from reduced cooling efficiency and may blow warm air. Low refrigerant can also cause the evaporator coils to freeze solid.
A frozen coil can lead to a water leak when the ice melts, masking the underlying refrigerant issue. If your AC Fan Runs but Compressor Won't Start, a refrigerant leak could be the cause.
Health risks are also a concern. Refrigerant exposure can cause dizziness and breathing difficulties. If you suspect a leak, turn off the AC and ventilate the area.
The most costly risk is compressor damage. The compressor overworks to compensate for low refrigerant, leading to overheating and failure. Catching leaks early can save you from an expensive compressor replacement.
What Causes Refrigerant Leaks?
Refrigerant leaks develop over time. Normal vibrations can loosen connections or create small stress fractures in the refrigerant lines.
Formicary corrosion is another common cause. Household chemicals can react with moisture on copper pipes, creating formic acid that eats tiny pinhole leaks into the metal over time.
The system's seals and valves can also wear out from heat, chemicals, and vibration, becoming brittle and losing their tight seal.
Physical damage from lawnmowers, tree branches, or improper installation can also cause leaks. This damage can contribute to other issues, like Why AC Freezes Up in Hot Summers.
Bottom line: Refrigerant leaks are serious and require a certified HVAC technician to safely diagnose, repair, and recharge your system.
Your Action Plan: DIY Fixes vs. Calling a Professional
When you find a leaking AC unit, you must decide whether to fix it yourself or call a professional. The answer depends on the cause and your comfort level with DIY repairs.
Many water leaks have simple DIY solutions. However, knowing your limits is crucial for safety and to avoid turning a minor repair into a major expense.
Safety always comes first. If you're unsure, call a professional. Also, check your warranty, as some DIY repairs can void it.
Simple DIY Fixes You Can Try
Several common causes of AC water leaks are easy to fix yourself.
Changing your air filter is the easiest fix. A dirty filter restricts airflow, causing the evaporator coil to freeze. When the ice melts, it can overwhelm the drain pan. Replace your filter every 1-3 months for efficiency and to prevent leaks.
Clearing a clogged condensate drain line is another DIY task. Use a wet/dry vacuum on the outdoor end of the pipe to suck out the clog. Alternatively, pour distilled white vinegar down the indoor access point, let it sit for 30 minutes, and then flush with water. Avoid using bleach.
Check your thermostat settings. Ensure it's set to "cool" and the fan is on "auto." A constantly running fan can cause issues with condensation. For more help, see our AC Thermostat Problems Troubleshooting Guide.
Ensure all vents are open. Blocked vents restrict airflow, which can lead to frozen coils. Check that furniture or other items are not blocking any supply or return vents.
When to Call an HVAC Technician
Some AC problems require a professional because they are either too risky for DIY or require specialized tools and training.
- Suspected refrigerant leak: Call a professional immediately. Hissing sounds, chemical smells, or oily residue are red flags. Handling refrigerant is illegal for unlicensed individuals and poses health risks.
- Persistent frozen coils: If coils keep freezing after you've changed the filter and checked airflow, it likely indicates low refrigerant or another serious issue requiring professional diagnosis.
- Electrical issues: Never attempt DIY electrical repairs. If you see flickering lights, trip breakers, or smell burning, turn off the system and call an expert immediately.
- Major component failures: Damaged drain pans, broken condensate pumps, or compressor problems require professional tools and expertise.
- Significant water damage: If the leak has caused major water damage, you'll need professional AC repair and possibly water damage mitigation to prevent mold.
- DIY fixes don't work: If you've tried the simple fixes and the leak persists, it's time for an expert to diagnose a potentially more complex underlying issue.
For expert help in the Kansas City area, contact our team for AC Repair Lenexa KS. We also offer 24/7 AC Repair Overland Park KS for emergencies.
Frequently Asked Questions about Leaking AC Units
Dealing with a leaking AC unit brings up many questions. Here are answers to the most common ones we hear from homeowners in the Kansas City area.
Can I still use my AC if it's leaking water?
No. You should turn your AC off immediately if it's leaking water. Continuing to run it can cause significant problems.
Running a leaking AC leads to costly issues. Water damage can spread quickly to floors, walls, and ceilings, leading to expensive structural repairs. Mold growth can begin within 24-48 hours in standing water, causing musty smells and triggering respiratory issues. There is also an electrical hazard, as water near electrical components can cause short circuits, permanent damage, or even a fire. Running the unit will only make the underlying problem worse.
How can I prevent my AC from leaking in the future?
Most AC leaks are preventable with basic maintenance.
- Regular filter changes are crucial. A clean filter prevents frozen coils. Check your filter monthly and replace it if it's dirty (typically every 1-3 months).
- Annual drain line maintenance is also key. Flushing the line annually removes buildup and prevents clogs, saving you from emergency summer repairs.
- Professional tune-ups allow a technician to spot potential issues like cracks, early leaks, or worn components. Catching problems early prevents expensive emergency repairs.
Our AC Maintenance Plan Guide 2025 outlines what preventive maintenance should include and how it protects your investment.
What are the consequences of ignoring an AC leak?
Ignoring a leaking AC unit will only lead to bigger problems and higher repair bills.
- Water damage can escalate quickly, leading to warped floors, stained ceilings, and damaged drywall.
- Mold and mildew will grow, affecting your home's air quality and potentially causing respiratory issues.
- Electrical problems can occur if water reaches wiring, leading to short circuits and safety hazards.
- Your utility bills will increase as the inefficient system works harder.
- The stress can lead to complete system failure, requiring a full replacement instead of a simple repair.
Keep Your Cool and Your Home Dry
A leaking AC unit can be overwhelming, but with the right knowledge, you can handle it. Quick action is key to preventing a minor issue from becoming a major repair.
The path is straightforward: Identify the leak. Puddles and musty smells suggest a water issue you might fix yourself. Hissing sounds and chemical odors indicate a refrigerant leak that requires a professional.
Water leaks are often caused by a dirty air filter or a clogged drain line. These are simple, DIY-friendly fixes that can save you time and money.
However, know your limits to stay safe and save money. Refrigerant leaks, persistent frozen coils, electrical issues, and major component failures are not DIY jobs and require a certified HVAC technician.
The best way to avoid future leaks is prevention through regular maintenance. Change your filter regularly and schedule annual professional tune-ups to prevent unexpected breakdowns during hot Kansas summers.
At Patriot Heating & AC, we help homeowners across the greater Kansas City area, including Shawnee, Overland Park, Lenexa, Olathe, and Leawood, resolve AC leak emergencies. We are your partners in maintaining a comfortable home year-round.
When you need reliable repair, don't hesitate to reach out. For expert service in the Lenexa area, trust a certified HVAC contractor. Your comfort is worth it.
When Your AC Unit Starts Leaking: Quick Signs and Causes
A leaking AC unit is a common HVAC problem, especially during hot Kansas summers. Water pooling indoors or dripping from the ceiling can quickly escalate from an annoyance to a costly repair.
Quick troubleshooting for a leaking AC unit:
- Turn off your AC immediately to prevent further damage
- Check for water puddles around the indoor unit (indicates water leak)
- Listen for hissing sounds near refrigerant lines (indicates refrigerant leak)
- Look for ice buildup on evaporator coils (sign of airflow problems)
- Inspect your air filter - if dirty, replace it immediately
- Call a professional if you suspect refrigerant leak or see significant water damage
The good news is many leaks have simple, DIY-friendly causes. A clogged condensate drain line is the most common culprit for water leaks, followed by dirty air filters that restrict airflow and freeze evaporator coils.
However, not all AC leaks are the same. Water leaks are often DIY-friendly, but refrigerant leaks require a different approach, posing health risks that demand professional attention.
This guide will help you identify your leak, understand its cause, and decide whether to DIY the fix or call an expert.
Is It Water or Refrigerant? How to Identify Your AC Leak
If you find a leaking AC unit, act quickly. First, identify if it's water or refrigerant. This determines your next steps and ensures your family's safety.
Turn off your AC immediately. Running a leaking system makes the problem worse and creates a risk of electrical shorts or fires if water is near electrical components. Safety first.
With the system off, you can investigate. Water and refrigerant leaks have distinct signs.
Water Leak Symptoms
Water leaks are more common and usually less serious. Your AC naturally creates water during cooling, which should drain away. A leak means this process has failed.
Puddles of water are the main clue, typically found around the indoor unit or dripping from the ceiling if the unit is in the attic. If you have standing water in your drain pan, see our guide on Fix a Flooded AC Drain Pan in Homes.
A persistent dripping sound, even when the AC is off, often indicates a water leak.
A musty, damp smell suggests mold and mildew are growing in standing water from the leak.
Another sign is increased indoor humidity. A leaking AC can't dehumidify effectively, making your home feel sticky even if it's cool.
Refrigerant Leak Symptoms
Refrigerant leaks are serious and require immediate professional attention. This chemical cools your air, and a leak causes performance issues and health hazards.
Hissing or bubbling sounds are a key sign. Refrigerant escapes under pressure, sounding like air leaking from a tire.
An oily residue on copper refrigerant lines or coils is another clue. The oil is a lubricant mixed with the refrigerant.
A faint, sweet chemical smell can also indicate a refrigerant leak, different from the musty odor of a water leak.
The biggest sign is poor performance. If your AC blows warm air or runs constantly without cooling, low refrigerant is a likely cause. See our guide on AC Blowing Warm Air Fixes for Homeowners for more tips.
Refrigerant leaks can also cause evaporator coils to freeze. When the ice melts, it creates a water leak, masking the true refrigerant problem. Our guide on Troubleshooting AC Refrigerant Leak Signs can help clarify this.
| Symptom Category | Water Leak (Typically) | Refrigerant Leak (Typically) |
|---|---|---|
| Appearance | Puddles, drips, water stains | Oily residue on coils/pipes, ice buildup on evaporator coils |
| Sound | Dripping, gurgling (if drain line is clogged) | Hissing, bubbling, gurgling |
| Smell | Musty, damp, moldy | Sweet, chemical (can be faint or absent) |
| AC Performance | May still cool, but often with increased humidity | Poor cooling, warm air, unit runs constantly but inefficiently |
When in doubt, call a professional. If you see multiple symptoms or are unsure of the leak type, it's safer to get an expert opinion. Your safety and comfort are worth the service call.
Common Causes of a Water-Leaking AC Unit
To understand why your leaking AC unit is leaking water, you need to know how it handles moisture. Your AC pulls warm, humid air over cold evaporator coils, causing moisture to condense, much like on a cold glass.
Normally, this water drips into a condensate pan and flows outside through a drain line. When this system fails, water leaks into your home.
Here are the most common causes of water leaks.
Clogged Condensate Drain Line
A clogged condensate drain line is the #1 cause of a leaking AC unit. This PVC pipe is responsible for most AC water leaks in Kansas homes.
Over time, dirt, debris, algae, and mold can accumulate in the drain line, forming a clog that blocks water flow.
The water then backs up and causes the drain pan to overflow. Fortunately, this is often an easy fix if caught early.
If you're dealing with this issue in the Shawnee area, check out our guide on When AC Drain Line Clogs in Shawnee. For a step-by-step approach to clearing the clog yourself, this resource explains How to clean a clogged AC drain line.
Dirty Air Filter
Surprisingly, a dirty air filter can cause a water leak. A clogged filter leads to a chain of events that results in water on your floor.
When a dirty filter restricts airflow, it prevents warm air from reaching the evaporator coil. This causes the coil to get too cold and freeze solid.
When the ice melts, the sudden rush of water can overwhelm the drain pan, causing it to overflow.
This is why we always recommend checking your air filter first when you find a water leak. Need help with proper filter maintenance? Here's a helpful guide on How to clean an AC filter. If you're in our service area and need professional AC maintenance, we offer AC Services Shawnee KS.
Damaged or Rusted Drain Pan
The condensate drain pan collects moisture from the evaporator coil but can wear out over time due to age and corrosion, especially in older units.
Metal pans can rust, creating cracks or holes that allow water to drip through instead of flowing to the drain line.
Systems have a primary drain pan under the coil and often a secondary drain pan underneath the unit as a backup, especially in attics.
If you notice water dripping through the pan rather than overflowing from the edges, you're likely dealing with a damaged pan that needs replacement.
Broken Condensate Pump
Basement or attic units often use a condensate pump to actively push water outside through the drain line.
A pump can fail due to electrical malfunction, mechanical breakdown, or clogs. A failed pump leads to water overflow and leaks.
Pump issues often involve electrical components and require professional repair. If your unit has a pump and is leaking, contact a service like AC Repair Olathe KS for safe repairs.
Understanding Refrigerant Leaks and Their Dangers
Unlike water leaks, refrigerant leaks are a serious challenge requiring immediate attention. Your AC is a closed-loop system, meaning refrigerant circulates without needing a refill. When it escapes, your comfort and safety are at risk.
The Role and Risks of a Leaking AC Unit with Low Refrigerant
Refrigerant is your AC's heat transfer fluid. It works by changing from liquid to gas, absorbing indoor heat at the evaporator coil and releasing it outside at the condenser coil. This cycle cools your home.
When a leaking AC unit loses refrigerant, it suffers from reduced cooling efficiency and may blow warm air. Low refrigerant can also cause the evaporator coils to freeze solid.
A frozen coil can lead to a water leak when the ice melts, masking the underlying refrigerant issue. If your AC Fan Runs but Compressor Won't Start, a refrigerant leak could be the cause.
Health risks are also a concern. Refrigerant exposure can cause dizziness and breathing difficulties. If you suspect a leak, turn off the AC and ventilate the area.
The most costly risk is compressor damage. The compressor overworks to compensate for low refrigerant, leading to overheating and failure. Catching leaks early can save you from an expensive compressor replacement.
What Causes Refrigerant Leaks?
Refrigerant leaks develop over time. Normal vibrations can loosen connections or create small stress fractures in the refrigerant lines.
Formicary corrosion is another common cause. Household chemicals can react with moisture on copper pipes, creating formic acid that eats tiny pinhole leaks into the metal over time.
The system's seals and valves can also wear out from heat, chemicals, and vibration, becoming brittle and losing their tight seal.
Physical damage from lawnmowers, tree branches, or improper installation can also cause leaks. This damage can contribute to other issues, like Why AC Freezes Up in Hot Summers.
Bottom line: Refrigerant leaks are serious and require a certified HVAC technician to safely diagnose, repair, and recharge your system.
Your Action Plan: DIY Fixes vs. Calling a Professional
When you find a leaking AC unit, you must decide whether to fix it yourself or call a professional. The answer depends on the cause and your comfort level with DIY repairs.
Many water leaks have simple DIY solutions. However, knowing your limits is crucial for safety and to avoid turning a minor repair into a major expense.
Safety always comes first. If you're unsure, call a professional. Also, check your warranty, as some DIY repairs can void it.
Simple DIY Fixes You Can Try
Several common causes of AC water leaks are easy to fix yourself.
Changing your air filter is the easiest fix. A dirty filter restricts airflow, causing the evaporator coil to freeze. When the ice melts, it can overwhelm the drain pan. Replace your filter every 1-3 months for efficiency and to prevent leaks.
Clearing a clogged condensate drain line is another DIY task. Use a wet/dry vacuum on the outdoor end of the pipe to suck out the clog. Alternatively, pour distilled white vinegar down the indoor access point, let it sit for 30 minutes, and then flush with water. Avoid using bleach.
Check your thermostat settings. Ensure it's set to "cool" and the fan is on "auto." A constantly running fan can cause issues with condensation. For more help, see our AC Thermostat Problems Troubleshooting Guide.
Ensure all vents are open. Blocked vents restrict airflow, which can lead to frozen coils. Check that furniture or other items are not blocking any supply or return vents.
When to Call an HVAC Technician
Some AC problems require a professional because they are either too risky for DIY or require specialized tools and training.
- Suspected refrigerant leak: Call a professional immediately. Hissing sounds, chemical smells, or oily residue are red flags. Handling refrigerant is illegal for unlicensed individuals and poses health risks.
- Persistent frozen coils: If coils keep freezing after you've changed the filter and checked airflow, it likely indicates low refrigerant or another serious issue requiring professional diagnosis.
- Electrical issues: Never attempt DIY electrical repairs. If you see flickering lights, trip breakers, or smell burning, turn off the system and call an expert immediately.
- Major component failures: Damaged drain pans, broken condensate pumps, or compressor problems require professional tools and expertise.
- Significant water damage: If the leak has caused major water damage, you'll need professional AC repair and possibly water damage mitigation to prevent mold.
- DIY fixes don't work: If you've tried the simple fixes and the leak persists, it's time for an expert to diagnose a potentially more complex underlying issue.
For expert help in the Kansas City area, contact our team for AC Repair Lenexa KS. We also offer 24/7 AC Repair Overland Park KS for emergencies.
Frequently Asked Questions about Leaking AC Units
Dealing with a leaking AC unit brings up many questions. Here are answers to the most common ones we hear from homeowners in the Kansas City area.
Can I still use my AC if it's leaking water?
No. You should turn your AC off immediately if it's leaking water. Continuing to run it can cause significant problems.
Running a leaking AC leads to costly issues. Water damage can spread quickly to floors, walls, and ceilings, leading to expensive structural repairs. Mold growth can begin within 24-48 hours in standing water, causing musty smells and triggering respiratory issues. There is also an electrical hazard, as water near electrical components can cause short circuits, permanent damage, or even a fire. Running the unit will only make the underlying problem worse.
How can I prevent my AC from leaking in the future?
Most AC leaks are preventable with basic maintenance.
- Regular filter changes are crucial. A clean filter prevents frozen coils. Check your filter monthly and replace it if it's dirty (typically every 1-3 months).
- Annual drain line maintenance is also key. Flushing the line annually removes buildup and prevents clogs, saving you from emergency summer repairs.
- Professional tune-ups allow a technician to spot potential issues like cracks, early leaks, or worn components. Catching problems early prevents expensive emergency repairs.
Our AC Maintenance Plan Guide 2025 outlines what preventive maintenance should include and how it protects your investment.
What are the consequences of ignoring an AC leak?
Ignoring a leaking AC unit will only lead to bigger problems and higher repair bills.
- Water damage can escalate quickly, leading to warped floors, stained ceilings, and damaged drywall.
- Mold and mildew will grow, affecting your home's air quality and potentially causing respiratory issues.
- Electrical problems can occur if water reaches wiring, leading to short circuits and safety hazards.
- Your utility bills will increase as the inefficient system works harder.
- The stress can lead to complete system failure, requiring a full replacement instead of a simple repair.
Keep Your Cool and Your Home Dry
A leaking AC unit can be overwhelming, but with the right knowledge, you can handle it. Quick action is key to preventing a minor issue from becoming a major repair.
The path is straightforward: Identify the leak. Puddles and musty smells suggest a water issue you might fix yourself. Hissing sounds and chemical odors indicate a refrigerant leak that requires a professional.
Water leaks are often caused by a dirty air filter or a clogged drain line. These are simple, DIY-friendly fixes that can save you time and money.
However, know your limits to stay safe and save money. Refrigerant leaks, persistent frozen coils, electrical issues, and major component failures are not DIY jobs and require a certified HVAC technician.
The best way to avoid future leaks is prevention through regular maintenance. Change your filter regularly and schedule annual professional tune-ups to prevent unexpected breakdowns during hot Kansas summers.
At Patriot Heating & AC, we help homeowners across the greater Kansas City area, including Shawnee, Overland Park, Lenexa, Olathe, and Leawood, resolve AC leak emergencies. We are your partners in maintaining a comfortable home year-round.
When you need reliable repair, don't hesitate to reach out. For expert service in the Lenexa area, trust a certified HVAC contractor. Your comfort is worth it.
When Your AC Unit Starts Leaking: Quick Signs and Causes
A leaking AC unit is a common HVAC problem, especially during hot Kansas summers. Water pooling indoors or dripping from the ceiling can quickly escalate from an annoyance to a costly repair.
Quick troubleshooting for a leaking AC unit:
- Turn off your AC immediately to prevent further damage
- Check for water puddles around the indoor unit (indicates water leak)
- Listen for hissing sounds near refrigerant lines (indicates refrigerant leak)
- Look for ice buildup on evaporator coils (sign of airflow problems)
- Inspect your air filter - if dirty, replace it immediately
- Call a professional if you suspect refrigerant leak or see significant water damage
The good news is many leaks have simple, DIY-friendly causes. A clogged condensate drain line is the most common culprit for water leaks, followed by dirty air filters that restrict airflow and freeze evaporator coils.
However, not all AC leaks are the same. Water leaks are often DIY-friendly, but refrigerant leaks require a different approach, posing health risks that demand professional attention.
This guide will help you identify your leak, understand its cause, and decide whether to DIY the fix or call an expert.
Is It Water or Refrigerant? How to Identify Your AC Leak
If you find a leaking AC unit, act quickly. First, identify if it's water or refrigerant. This determines your next steps and ensures your family's safety.
Turn off your AC immediately. Running a leaking system makes the problem worse and creates a risk of electrical shorts or fires if water is near electrical components. Safety first.
With the system off, you can investigate. Water and refrigerant leaks have distinct signs.
Water Leak Symptoms
Water leaks are more common and usually less serious. Your AC naturally creates water during cooling, which should drain away. A leak means this process has failed.
Puddles of water are the main clue, typically found around the indoor unit or dripping from the ceiling if the unit is in the attic. If you have standing water in your drain pan, see our guide on Fix a Flooded AC Drain Pan in Homes.
A persistent dripping sound, even when the AC is off, often indicates a water leak.
A musty, damp smell suggests mold and mildew are growing in standing water from the leak.
Another sign is increased indoor humidity. A leaking AC can't dehumidify effectively, making your home feel sticky even if it's cool.
Refrigerant Leak Symptoms
Refrigerant leaks are serious and require immediate professional attention. This chemical cools your air, and a leak causes performance issues and health hazards.
Hissing or bubbling sounds are a key sign. Refrigerant escapes under pressure, sounding like air leaking from a tire.
An oily residue on copper refrigerant lines or coils is another clue. The oil is a lubricant mixed with the refrigerant.
A faint, sweet chemical smell can also indicate a refrigerant leak, different from the musty odor of a water leak.
The biggest sign is poor performance. If your AC blows warm air or runs constantly without cooling, low refrigerant is a likely cause. See our guide on AC Blowing Warm Air Fixes for Homeowners for more tips.
Refrigerant leaks can also cause evaporator coils to freeze. When the ice melts, it creates a water leak, masking the true refrigerant problem. Our guide on Troubleshooting AC Refrigerant Leak Signs can help clarify this.
| Symptom Category | Water Leak (Typically) | Refrigerant Leak (Typically) |
|---|---|---|
| Appearance | Puddles, drips, water stains | Oily residue on coils/pipes, ice buildup on evaporator coils |
| Sound | Dripping, gurgling (if drain line is clogged) | Hissing, bubbling, gurgling |
| Smell | Musty, damp, moldy | Sweet, chemical (can be faint or absent) |
| AC Performance | May still cool, but often with increased humidity | Poor cooling, warm air, unit runs constantly but inefficiently |
When in doubt, call a professional. If you see multiple symptoms or are unsure of the leak type, it's safer to get an expert opinion. Your safety and comfort are worth the service call.
Common Causes of a Water-Leaking AC Unit
To understand why your leaking AC unit is leaking water, you need to know how it handles moisture. Your AC pulls warm, humid air over cold evaporator coils, causing moisture to condense, much like on a cold glass.
Normally, this water drips into a condensate pan and flows outside through a drain line. When this system fails, water leaks into your home.
Here are the most common causes of water leaks.
Clogged Condensate Drain Line
A clogged condensate drain line is the #1 cause of a leaking AC unit. This PVC pipe is responsible for most AC water leaks in Kansas homes.
Over time, dirt, debris, algae, and mold can accumulate in the drain line, forming a clog that blocks water flow.
The water then backs up and causes the drain pan to overflow. Fortunately, this is often an easy fix if caught early.
If you're dealing with this issue in the Shawnee area, check out our guide on When AC Drain Line Clogs in Shawnee. For a step-by-step approach to clearing the clog yourself, this resource explains How to clean a clogged AC drain line.
Dirty Air Filter
Surprisingly, a dirty air filter can cause a water leak. A clogged filter leads to a chain of events that results in water on your floor.
When a dirty filter restricts airflow, it prevents warm air from reaching the evaporator coil. This causes the coil to get too cold and freeze solid.
When the ice melts, the sudden rush of water can overwhelm the drain pan, causing it to overflow.
This is why we always recommend checking your air filter first when you find a water leak. Need help with proper filter maintenance? Here's a helpful guide on How to clean an AC filter. If you're in our service area and need professional AC maintenance, we offer AC Services Shawnee KS.
Damaged or Rusted Drain Pan
The condensate drain pan collects moisture from the evaporator coil but can wear out over time due to age and corrosion, especially in older units.
Metal pans can rust, creating cracks or holes that allow water to drip through instead of flowing to the drain line.
Systems have a primary drain pan under the coil and often a secondary drain pan underneath the unit as a backup, especially in attics.
If you notice water dripping through the pan rather than overflowing from the edges, you're likely dealing with a damaged pan that needs replacement.
Broken Condensate Pump
Basement or attic units often use a condensate pump to actively push water outside through the drain line.
A pump can fail due to electrical malfunction, mechanical breakdown, or clogs. A failed pump leads to water overflow and leaks.
Pump issues often involve electrical components and require professional repair. If your unit has a pump and is leaking, contact a service like AC Repair Olathe KS for safe repairs.
Understanding Refrigerant Leaks and Their Dangers
Unlike water leaks, refrigerant leaks are a serious challenge requiring immediate attention. Your AC is a closed-loop system, meaning refrigerant circulates without needing a refill. When it escapes, your comfort and safety are at risk.
The Role and Risks of a Leaking AC Unit with Low Refrigerant
Refrigerant is your AC's heat transfer fluid. It works by changing from liquid to gas, absorbing indoor heat at the evaporator coil and releasing it outside at the condenser coil. This cycle cools your home.
When a leaking AC unit loses refrigerant, it suffers from reduced cooling efficiency and may blow warm air. Low refrigerant can also cause the evaporator coils to freeze solid.
A frozen coil can lead to a water leak when the ice melts, masking the underlying refrigerant issue. If your AC Fan Runs but Compressor Won't Start, a refrigerant leak could be the cause.
Health risks are also a concern. Refrigerant exposure can cause dizziness and breathing difficulties. If you suspect a leak, turn off the AC and ventilate the area.
The most costly risk is compressor damage. The compressor overworks to compensate for low refrigerant, leading to overheating and failure. Catching leaks early can save you from an expensive compressor replacement.
What Causes Refrigerant Leaks?
Refrigerant leaks develop over time. Normal vibrations can loosen connections or create small stress fractures in the refrigerant lines.
Formicary corrosion is another common cause. Household chemicals can react with moisture on copper pipes, creating formic acid that eats tiny pinhole leaks into the metal over time.
The system's seals and valves can also wear out from heat, chemicals, and vibration, becoming brittle and losing their tight seal.
Physical damage from lawnmowers, tree branches, or improper installation can also cause leaks. This damage can contribute to other issues, like Why AC Freezes Up in Hot Summers.
Bottom line: Refrigerant leaks are serious and require a certified HVAC technician to safely diagnose, repair, and recharge your system.
Your Action Plan: DIY Fixes vs. Calling a Professional
When you find a leaking AC unit, you must decide whether to fix it yourself or call a professional. The answer depends on the cause and your comfort level with DIY repairs.
Many water leaks have simple DIY solutions. However, knowing your limits is crucial for safety and to avoid turning a minor repair into a major expense.
Safety always comes first. If you're unsure, call a professional. Also, check your warranty, as some DIY repairs can void it.
Simple DIY Fixes You Can Try
Several common causes of AC water leaks are easy to fix yourself.
Changing your air filter is the easiest fix. A dirty filter restricts airflow, causing the evaporator coil to freeze. When the ice melts, it can overwhelm the drain pan. Replace your filter every 1-3 months for efficiency and to prevent leaks.
Clearing a clogged condensate drain line is another DIY task. Use a wet/dry vacuum on the outdoor end of the pipe to suck out the clog. Alternatively, pour distilled white vinegar down the indoor access point, let it sit for 30 minutes, and then flush with water. Avoid using bleach.
Check your thermostat settings. Ensure it's set to "cool" and the fan is on "auto." A constantly running fan can cause issues with condensation. For more help, see our AC Thermostat Problems Troubleshooting Guide.
Ensure all vents are open. Blocked vents restrict airflow, which can lead to frozen coils. Check that furniture or other items are not blocking any supply or return vents.
When to Call an HVAC Technician
Some AC problems require a professional because they are either too risky for DIY or require specialized tools and training.
- Suspected refrigerant leak: Call a professional immediately. Hissing sounds, chemical smells, or oily residue are red flags. Handling refrigerant is illegal for unlicensed individuals and poses health risks.
- Persistent frozen coils: If coils keep freezing after you've changed the filter and checked airflow, it likely indicates low refrigerant or another serious issue requiring professional diagnosis.
- Electrical issues: Never attempt DIY electrical repairs. If you see flickering lights, trip breakers, or smell burning, turn off the system and call an expert immediately.
- Major component failures: Damaged drain pans, broken condensate pumps, or compressor problems require professional tools and expertise.
- Significant water damage: If the leak has caused major water damage, you'll need professional AC repair and possibly water damage mitigation to prevent mold.
- DIY fixes don't work: If you've tried the simple fixes and the leak persists, it's time for an expert to diagnose a potentially more complex underlying issue.
For expert help in the Kansas City area, contact our team for AC Repair Lenexa KS. We also offer 24/7 AC Repair Overland Park KS for emergencies.
Frequently Asked Questions about Leaking AC Units
Dealing with a leaking AC unit brings up many questions. Here are answers to the most common ones we hear from homeowners in the Kansas City area.
Can I still use my AC if it's leaking water?
No. You should turn your AC off immediately if it's leaking water. Continuing to run it can cause significant problems.
Running a leaking AC leads to costly issues. Water damage can spread quickly to floors, walls, and ceilings, leading to expensive structural repairs. Mold growth can begin within 24-48 hours in standing water, causing musty smells and triggering respiratory issues. There is also an electrical hazard, as water near electrical components can cause short circuits, permanent damage, or even a fire. Running the unit will only make the underlying problem worse.
How can I prevent my AC from leaking in the future?
Most AC leaks are preventable with basic maintenance.
- Regular filter changes are crucial. A clean filter prevents frozen coils. Check your filter monthly and replace it if it's dirty (typically every 1-3 months).
- Annual drain line maintenance is also key. Flushing the line annually removes buildup and prevents clogs, saving you from emergency summer repairs.
- Professional tune-ups allow a technician to spot potential issues like cracks, early leaks, or worn components. Catching problems early prevents expensive emergency repairs.
Our AC Maintenance Plan Guide 2025 outlines what preventive maintenance should include and how it protects your investment.
What are the consequences of ignoring an AC leak?
Ignoring a leaking AC unit will only lead to bigger problems and higher repair bills.
- Water damage can escalate quickly, leading to warped floors, stained ceilings, and damaged drywall.
- Mold and mildew will grow, affecting your home's air quality and potentially causing respiratory issues.
- Electrical problems can occur if water reaches wiring, leading to short circuits and safety hazards.
- Your utility bills will increase as the inefficient system works harder.
- The stress can lead to complete system failure, requiring a full replacement instead of a simple repair.
Keep Your Cool and Your Home Dry
A leaking AC unit can be overwhelming, but with the right knowledge, you can handle it. Quick action is key to preventing a minor issue from becoming a major repair.
The path is straightforward: Identify the leak. Puddles and musty smells suggest a water issue you might fix yourself. Hissing sounds and chemical odors indicate a refrigerant leak that requires a professional.
Water leaks are often caused by a dirty air filter or a clogged drain line. These are simple, DIY-friendly fixes that can save you time and money.
However, know your limits to stay safe and save money. Refrigerant leaks, persistent frozen coils, electrical issues, and major component failures are not DIY jobs and require a certified HVAC technician.
The best way to avoid future leaks is prevention through regular maintenance. Change your filter regularly and schedule annual professional tune-ups to prevent unexpected breakdowns during hot Kansas summers.
At Patriot Heating & AC, we help homeowners across the greater Kansas City area, including Shawnee, Overland Park, Lenexa, Olathe, and Leawood, resolve AC leak emergencies. We are your partners in maintaining a comfortable home year-round.
When you need reliable repair, don't hesitate to reach out. For expert service in the Lenexa area, trust a certified HVAC contractor. Your comfort is worth it.
When Your AC Unit Starts Leaking: Quick Signs and Causes
A leaking AC unit is a common HVAC problem, especially during hot Kansas summers. Water pooling indoors or dripping from the ceiling can quickly escalate from an annoyance to a costly repair.
Quick troubleshooting for a leaking AC unit:
- Turn off your AC immediately to prevent further damage
- Check for water puddles around the indoor unit (indicates water leak)
- Listen for hissing sounds near refrigerant lines (indicates refrigerant leak)
- Look for ice buildup on evaporator coils (sign of airflow problems)
- Inspect your air filter - if dirty, replace it immediately
- Call a professional if you suspect refrigerant leak or see significant water damage
The good news is many leaks have simple, DIY-friendly causes. A clogged condensate drain line is the most common culprit for water leaks, followed by dirty air filters that restrict airflow and freeze evaporator coils.
However, not all AC leaks are the same. Water leaks are often DIY-friendly, but refrigerant leaks require a different approach, posing health risks that demand professional attention.
This guide will help you identify your leak, understand its cause, and decide whether to DIY the fix or call an expert.
Is It Water or Refrigerant? How to Identify Your AC Leak
If you find a leaking AC unit, act quickly. First, identify if it's water or refrigerant. This determines your next steps and ensures your family's safety.
Turn off your AC immediately. Running a leaking system makes the problem worse and creates a risk of electrical shorts or fires if water is near electrical components. Safety first.
With the system off, you can investigate. Water and refrigerant leaks have distinct signs.
Water Leak Symptoms
Water leaks are more common and usually less serious. Your AC naturally creates water during cooling, which should drain away. A leak means this process has failed.
Puddles of water are the main clue, typically found around the indoor unit or dripping from the ceiling if the unit is in the attic. If you have standing water in your drain pan, see our guide on Fix a Flooded AC Drain Pan in Homes.
A persistent dripping sound, even when the AC is off, often indicates a water leak.
A musty, damp smell suggests mold and mildew are growing in standing water from the leak.
Another sign is increased indoor humidity. A leaking AC can't dehumidify effectively, making your home feel sticky even if it's cool.
Refrigerant Leak Symptoms
Refrigerant leaks are serious and require immediate professional attention. This chemical cools your air, and a leak causes performance issues and health hazards.
Hissing or bubbling sounds are a key sign. Refrigerant escapes under pressure, sounding like air leaking from a tire.
An oily residue on copper refrigerant lines or coils is another clue. The oil is a lubricant mixed with the refrigerant.
A faint, sweet chemical smell can also indicate a refrigerant leak, different from the musty odor of a water leak.
The biggest sign is poor performance. If your AC blows warm air or runs constantly without cooling, low refrigerant is a likely cause. See our guide on AC Blowing Warm Air Fixes for Homeowners for more tips.
Refrigerant leaks can also cause evaporator coils to freeze. When the ice melts, it creates a water leak, masking the true refrigerant problem. Our guide on Troubleshooting AC Refrigerant Leak Signs can help clarify this.
| Symptom Category | Water Leak (Typically) | Refrigerant Leak (Typically) |
|---|---|---|
| Appearance | Puddles, drips, water stains | Oily residue on coils/pipes, ice buildup on evaporator coils |
| Sound | Dripping, gurgling (if drain line is clogged) | Hissing, bubbling, gurgling |
| Smell | Musty, damp, moldy | Sweet, chemical (can be faint or absent) |
| AC Performance | May still cool, but often with increased humidity | Poor cooling, warm air, unit runs constantly but inefficiently |
When in doubt, call a professional. If you see multiple symptoms or are unsure of the leak type, it's safer to get an expert opinion. Your safety and comfort are worth the service call.
Common Causes of a Water-Leaking AC Unit
To understand why your leaking AC unit is leaking water, you need to know how it handles moisture. Your AC pulls warm, humid air over cold evaporator coils, causing moisture to condense, much like on a cold glass.
Normally, this water drips into a condensate pan and flows outside through a drain line. When this system fails, water leaks into your home.
Here are the most common causes of water leaks.
Clogged Condensate Drain Line
A clogged condensate drain line is the #1 cause of a leaking AC unit. This PVC pipe is responsible for most AC water leaks in Kansas homes.
Over time, dirt, debris, algae, and mold can accumulate in the drain line, forming a clog that blocks water flow.
The water then backs up and causes the drain pan to overflow. Fortunately, this is often an easy fix if caught early.
If you're dealing with this issue in the Shawnee area, check out our guide on When AC Drain Line Clogs in Shawnee. For a step-by-step approach to clearing the clog yourself, this resource explains How to clean a clogged AC drain line.
Dirty Air Filter
Surprisingly, a dirty air filter can cause a water leak. A clogged filter leads to a chain of events that results in water on your floor.
When a dirty filter restricts airflow, it prevents warm air from reaching the evaporator coil. This causes the coil to get too cold and freeze solid.
When the ice melts, the sudden rush of water can overwhelm the drain pan, causing it to overflow.
This is why we always recommend checking your air filter first when you find a water leak. Need help with proper filter maintenance? Here's a helpful guide on How to clean an AC filter. If you're in our service area and need professional AC maintenance, we offer AC Services Shawnee KS.
Damaged or Rusted Drain Pan
The condensate drain pan collects moisture from the evaporator coil but can wear out over time due to age and corrosion, especially in older units.
Metal pans can rust, creating cracks or holes that allow water to drip through instead of flowing to the drain line.
Systems have a primary drain pan under the coil and often a secondary drain pan underneath the unit as a backup, especially in attics.
If you notice water dripping through the pan rather than overflowing from the edges, you're likely dealing with a damaged pan that needs replacement.
Broken Condensate Pump
Basement or attic units often use a condensate pump to actively push water outside through the drain line.
A pump can fail due to electrical malfunction, mechanical breakdown, or clogs. A failed pump leads to water overflow and leaks.
Pump issues often involve electrical components and require professional repair. If your unit has a pump and is leaking, contact a service like AC Repair Olathe KS for safe repairs.
Understanding Refrigerant Leaks and Their Dangers
Unlike water leaks, refrigerant leaks are a serious challenge requiring immediate attention. Your AC is a closed-loop system, meaning refrigerant circulates without needing a refill. When it escapes, your comfort and safety are at risk.
The Role and Risks of a Leaking AC Unit with Low Refrigerant
Refrigerant is your AC's heat transfer fluid. It works by changing from liquid to gas, absorbing indoor heat at the evaporator coil and releasing it outside at the condenser coil. This cycle cools your home.
When a leaking AC unit loses refrigerant, it suffers from reduced cooling efficiency and may blow warm air. Low refrigerant can also cause the evaporator coils to freeze solid.
A frozen coil can lead to a water leak when the ice melts, masking the underlying refrigerant issue. If your AC Fan Runs but Compressor Won't Start, a refrigerant leak could be the cause.
Health risks are also a concern. Refrigerant exposure can cause dizziness and breathing difficulties. If you suspect a leak, turn off the AC and ventilate the area.
The most costly risk is compressor damage. The compressor overworks to compensate for low refrigerant, leading to overheating and failure. Catching leaks early can save you from an expensive compressor replacement.
What Causes Refrigerant Leaks?
Refrigerant leaks develop over time. Normal vibrations can loosen connections or create small stress fractures in the refrigerant lines.
Formicary corrosion is another common cause. Household chemicals can react with moisture on copper pipes, creating formic acid that eats tiny pinhole leaks into the metal over time.
The system's seals and valves can also wear out from heat, chemicals, and vibration, becoming brittle and losing their tight seal.
Physical damage from lawnmowers, tree branches, or improper installation can also cause leaks. This damage can contribute to other issues, like Why AC Freezes Up in Hot Summers.
Bottom line: Refrigerant leaks are serious and require a certified HVAC technician to safely diagnose, repair, and recharge your system.
Your Action Plan: DIY Fixes vs. Calling a Professional
When you find a leaking AC unit, you must decide whether to fix it yourself or call a professional. The answer depends on the cause and your comfort level with DIY repairs.
Many water leaks have simple DIY solutions. However, knowing your limits is crucial for safety and to avoid turning a minor repair into a major expense.
Safety always comes first. If you're unsure, call a professional. Also, check your warranty, as some DIY repairs can void it.
Simple DIY Fixes You Can Try
Several common causes of AC water leaks are easy to fix yourself.
Changing your air filter is the easiest fix. A dirty filter restricts airflow, causing the evaporator coil to freeze. When the ice melts, it can overwhelm the drain pan. Replace your filter every 1-3 months for efficiency and to prevent leaks.
Clearing a clogged condensate drain line is another DIY task. Use a wet/dry vacuum on the outdoor end of the pipe to suck out the clog. Alternatively, pour distilled white vinegar down the indoor access point, let it sit for 30 minutes, and then flush with water. Avoid using bleach.
Check your thermostat settings. Ensure it's set to "cool" and the fan is on "auto." A constantly running fan can cause issues with condensation. For more help, see our AC Thermostat Problems Troubleshooting Guide.
Ensure all vents are open. Blocked vents restrict airflow, which can lead to frozen coils. Check that furniture or other items are not blocking any supply or return vents.
When to Call an HVAC Technician
Some AC problems require a professional because they are either too risky for DIY or require specialized tools and training.
- Suspected refrigerant leak: Call a professional immediately. Hissing sounds, chemical smells, or oily residue are red flags. Handling refrigerant is illegal for unlicensed individuals and poses health risks.
- Persistent frozen coils: If coils keep freezing after you've changed the filter and checked airflow, it likely indicates low refrigerant or another serious issue requiring professional diagnosis.
- Electrical issues: Never attempt DIY electrical repairs. If you see flickering lights, trip breakers, or smell burning, turn off the system and call an expert immediately.
- Major component failures: Damaged drain pans, broken condensate pumps, or compressor problems require professional tools and expertise.
- Significant water damage: If the leak has caused major water damage, you'll need professional AC repair and possibly water damage mitigation to prevent mold.
- DIY fixes don't work: If you've tried the simple fixes and the leak persists, it's time for an expert to diagnose a potentially more complex underlying issue.
For expert help in the Kansas City area, contact our team for AC Repair Lenexa KS. We also offer 24/7 AC Repair Overland Park KS for emergencies.
Frequently Asked Questions about Leaking AC Units
Dealing with a leaking AC unit brings up many questions. Here are answers to the most common ones we hear from homeowners in the Kansas City area.
Can I still use my AC if it's leaking water?
No. You should turn your AC off immediately if it's leaking water. Continuing to run it can cause significant problems.
Running a leaking AC leads to costly issues. Water damage can spread quickly to floors, walls, and ceilings, leading to expensive structural repairs. Mold growth can begin within 24-48 hours in standing water, causing musty smells and triggering respiratory issues. There is also an electrical hazard, as water near electrical components can cause short circuits, permanent damage, or even a fire. Running the unit will only make the underlying problem worse.
How can I prevent my AC from leaking in the future?
Most AC leaks are preventable with basic maintenance.
- Regular filter changes are crucial. A clean filter prevents frozen coils. Check your filter monthly and replace it if it's dirty (typically every 1-3 months).
- Annual drain line maintenance is also key. Flushing the line annually removes buildup and prevents clogs, saving you from emergency summer repairs.
- Professional tune-ups allow a technician to spot potential issues like cracks, early leaks, or worn components. Catching problems early prevents expensive emergency repairs.
Our AC Maintenance Plan Guide 2025 outlines what preventive maintenance should include and how it protects your investment.
What are the consequences of ignoring an AC leak?
Ignoring a leaking AC unit will only lead to bigger problems and higher repair bills.
- Water damage can escalate quickly, leading to warped floors, stained ceilings, and damaged drywall.
- Mold and mildew will grow, affecting your home's air quality and potentially causing respiratory issues.
- Electrical problems can occur if water reaches wiring, leading to short circuits and safety hazards.
- Your utility bills will increase as the inefficient system works harder.
- The stress can lead to complete system failure, requiring a full replacement instead of a simple repair.
Keep Your Cool and Your Home Dry
A leaking AC unit can be overwhelming, but with the right knowledge, you can handle it. Quick action is key to preventing a minor issue from becoming a major repair.
The path is straightforward: Identify the leak. Puddles and musty smells suggest a water issue you might fix yourself. Hissing sounds and chemical odors indicate a refrigerant leak that requires a professional.
Water leaks are often caused by a dirty air filter or a clogged drain line. These are simple, DIY-friendly fixes that can save you time and money.
However, know your limits to stay safe and save money. Refrigerant leaks, persistent frozen coils, electrical issues, and major component failures are not DIY jobs and require a certified HVAC technician.
The best way to avoid future leaks is prevention through regular maintenance. Change your filter regularly and schedule annual professional tune-ups to prevent unexpected breakdowns during hot Kansas summers.
At Patriot Heating & AC, we help homeowners across the greater Kansas City area, including Shawnee, Overland Park, Lenexa, Olathe, and Leawood, resolve AC leak emergencies. We are your partners in maintaining a comfortable home year-round.
When you need reliable repair, don't hesitate to reach out. For expert service in the Lenexa area, trust a certified HVAC contractor. Your comfort is worth it.
Need Help? Call Patriot.
Call Us At: (913) 214-0883
Discover why so many homeowners trust Patriot Heating & AC with ALL of their Home Heating needs!
Customer Testimonials
See why customers trust our licensed and background-checked technicians and the quality service we deliver every time.
We’ve used Patriot for several years now and they always provide exceptional service. In particular, their technician, Gabe Simmons, is wonderful to work with. He has been the technician for our home for a few years now and always does a fantastic job. He’s friendly, welcoming, and remembers specifics about our home. I can’t recommend him enough.
Alex C.
I love the way Patriot is organized, and gives you updates as to when your technician will arrive. Cody was just a couple of minutes past the appointment time, and apologized for it. He was professional, courteous, and shared some great information about my furnace and air conditioner. I really like the way that Patriot gives you a printed maintenance checklist; what a great idea !
Ellen M.
We’ve had work done from Mike at Patriot a few different times and everything has been great. From replacing the entire HVAC system to tune ups, Mike has been extremely punctual, helpful, efficient, and friendly. We really appreciate his work and courteous manner with a house full of young kids. We will always call Patriot with our home needs as pricing, work, and staff have been superb. Thank you!
Matt S.
Mike did an excellent job working in my furnace and AC units to make sure they are running at peak performance. I am very pleased with Patriot and all they do for our families comfort. Justin came back out to replace the fan motor in the air conditioning unit on warranty. Thanks to both Mike and Justin for the excellent service.
Scott K.
Great service. Cody, the technician, is always polite, on time,, and always put plastic wraps on shoes before coming inside the house. I showed him today that my thermostat is off (according to my other 2 thermometers I put side by side). He called the company and they gave me the new one even it is after 3 years since I purchased the new system with them. Very honest company. Thank you.
v. s.
Look no further than Patriot Heating & AC for your service needs. I have used their services for the past 4 years now and have been completely satisfied. I have found them to be honest and professional as well as highly experienced. Frank was our technician today and he demonstrated all the values I have come to expect from Patriot Heating & Air. My expectations are "Perfection is the Standard". Patriot meets those expectations.
Dane R.
We’ve used Patriot for several years now and they always provide exceptional service. In particular, their technician, Gabe Simmons, is wonderful to work with. He has been the technician for our home for a few years now and always does a fantastic job. He’s friendly, welcoming, and remembers specifics about our home. I can’t recommend him enough.
Alex C.
I love the way Patriot is organized, and gives you updates as to when your technician will arrive. Cody was just a couple of minutes past the appointment time, and apologized for it. He was professional, courteous, and shared some great information about my furnace and air conditioner. I really like the way that Patriot gives you a printed maintenance checklist; what a great idea !
Ellen M.
We’ve had work done from Mike at Patriot a few different times and everything has been great. From replacing the entire HVAC system to tune ups, Mike has been extremely punctual, helpful, efficient, and friendly. We really appreciate his work and courteous manner with a house full of young kids. We will always call Patriot with our home needs as pricing, work, and staff have been superb. Thank you!
Matt S.
Mike did an excellent job working in my furnace and AC units to make sure they are running at peak performance. I am very pleased with Patriot and all they do for our families comfort. Justin came back out to replace the fan motor in the air conditioning unit on warranty. Thanks to both Mike and Justin for the excellent service.
Scott K.
Great service. Cody, the technician, is always polite, on time,, and always put plastic wraps on shoes before coming inside the house. I showed him today that my thermostat is off (according to my other 2 thermometers I put side by side). He called the company and they gave me the new one even it is after 3 years since I purchased the new system with them. Very honest company. Thank you.
v. s.
Look no further than Patriot Heating & AC for your service needs. I have used their services for the past 4 years now and have been completely satisfied. I have found them to be honest and professional as well as highly experienced. Frank was our technician today and he demonstrated all the values I have come to expect from Patriot Heating & Air. My expectations are "Perfection is the Standard". Patriot meets those expectations.
Dane R.
Customer Testimonials
See why customers trust our licensed and background-checked technicians and the quality service we deliver every time.
We’ve used Patriot for several years now and they always provide exceptional service. In particular, their technician, Gabe Simmons, is wonderful to work with. He has been the technician for our home for a few years now and always does a fantastic job. He’s friendly, welcoming, and remembers specifics about our home. I can’t recommend him enough.
Alex C.
I love the way Patriot is organized, and gives you updates as to when your technician will arrive. Cody was just a couple of minutes past the appointment time, and apologized for it. He was professional, courteous, and shared some great information about my furnace and air conditioner. I really like the way that Patriot gives you a printed maintenance checklist; what a great idea !
Ellen M.
We’ve had work done from Mike at Patriot a few different times and everything has been great. From replacing the entire HVAC system to tune ups, Mike has been extremely punctual, helpful, efficient, and friendly. We really appreciate his work and courteous manner with a house full of young kids. We will always call Patriot with our home needs as pricing, work, and staff have been superb. Thank you!
Matt S.
Mike did an excellent job working in my furnace and AC units to make sure they are running at peak performance. I am very pleased with Patriot and all they do for our families comfort. Justin came back out to replace the fan motor in the air conditioning unit on warranty. Thanks to both Mike and Justin for the excellent service.
Scott K.
Great service. Cody, the technician, is always polite, on time,, and always put plastic wraps on shoes before coming inside the house. I showed him today that my thermostat is off (according to my other 2 thermometers I put side by side). He called the company and they gave me the new one even it is after 3 years since I purchased the new system with them. Very honest company. Thank you.
v. s.
Look no further than Patriot Heating & AC for your service needs. I have used their services for the past 4 years now and have been completely satisfied. I have found them to be honest and professional as well as highly experienced. Frank was our technician today and he demonstrated all the values I have come to expect from Patriot Heating & Air. My expectations are "Perfection is the Standard". Patriot meets those expectations.
Dane R.
