Why Is My AC Leaking Water Inside? 5 Common Causes & What to Do
An Alarming Discovery: Water Leaking From Your AC
Finding a puddle of water under your indoor air conditioning unit is an alarming sight, especially in the middle of a hot South Carolina summer. The good news is that it’s a common problem with a clear set of causes. This article will explain why your AC is leaking water and exactly what you should do about it to protect your home.
Your Immediate First Step: Turn Off Your AC System
To prevent any further water damage to your floors, ceiling, or drywall, your first step should be to turn your cooling system completely OFF at the thermostat. This will stop the air conditioner from creating more condensation while you identify the problem.
The 5 Most Common Causes for a Leaking AC Unit
An indoor water leak from your AC is almost always related to an issue with its condensate drainage system. Here are the five most common culprits our technicians see every day.
1. A Clogged Condensate Drain Line
This is the #1 most common cause of a leaking AC. As your air conditioner removes humidity from the air, the collected water flows outside through a PVC drain line. Over time, this line can become clogged with sludge, algae, and dirt. When the water has nowhere to go, it backs up and overflows the drain pan inside your home. The best way to prevent this blockage is with annual routine maintenance, where technicians flush the line.
2. A Rusted or Damaged Drain Pan
The drain pan is located directly under your system’s indoor coils to catch condensation. If your system is over 10-12 years old, this metal pan can rust through or develop cracks. When this happens, water leaks directly through the damaged pan, even if the drain line itself is clear. The drain pan will need to be replaced by a qualified HVAC technician.
3. Frozen Evaporator Coils
A dirty air filter or a low refrigerant level can restrict airflow and cause the evaporator coils inside your unit to get too cold, forming a block of ice. When that ice eventually melts, the drain pan is overwhelmed by the large volume of water and overflows. If you notice reduced airflow from your vents along with the leak, frozen coils are a likely suspect. While you should check your air filter, if the problem persists it’s a sign of a more serious issue like a refrigerant leak that needs professional AC repair.
4. A Disconnected or Improperly Sloped Drain Line
Sometimes the solution is simple: the PVC drain line may have been knocked loose from the unit. In other cases, the line may not have been installed with the correct downward slope, causing water to pool and back up instead of draining away with gravity. This requires a professional to securely reconnect the line and ensure it has the proper slope.
5. A Broken Condensate Pump
If your indoor unit is located in a basement or attic, it likely uses a small pump to actively push the condensation outside. Like any mechanical part, this pump can wear out and fail. When the pump doesn’t turn on, the water will quickly overflow its reservoir, leading to a leak. The condensate pump will need to be repaired or replaced.
DIY vs. Calling for Help: What to Do Next
The only step you should take on your own is to check your air filter. If it’s dirty, replace it.
For all other issues—including clogged lines, a damaged pan, frozen coils, or a broken pump—it’s time to call a professional. These repairs require specialized tools, parts, and technical expertise to perform safely and correctly, and attempting a DIY fix can often lead to more significant and expensive damage.
Your Solution for a Leaking AC in Columbia, SC
If your AC is leaking water inside your Columbia or Lexington home, don’t wait for the problem to get worse and cause costly water damage. The certified technicians at Carolina Conditions can quickly diagnose the cause of the leak and provide an upfront price for the repair.
Call Carolina Conditions today at 803-233-7172 or schedule your service online and let us restore your peace of mind!
