Walking into your hallway, utility closet or basement only to find a puddle of water pooling around your indoor AC unit is an unwelcome surprise. While a small amount of outdoor condensation is a normal byproduct of a hard-working air conditioner, water leaking inside your house is a clear sign that something is wrong.
At CJ Hansen, we know that a leaking air conditioner can feel stressful, but don’t panic, the root cause is usually a straightforward issue.
An AC leaking water inside the home is most often caused by a clogged condensate drain line, a frozen evaporator coil due to a dirty air filter, low refrigerant levels or a damaged drain pan.
How does an AC produce water in the first place?
To understand a leak, it helps to know how your system handles moisture. Your air conditioner doesn’t just cool the air; it also acts as a powerful dehumidifier.
As warm, humid air from your home is pulled over the cold evaporator coil inside your indoor unit, moisture from the air condenses onto the coil, much like water droplets forming on the outside of a cold glass of iced water on a hot summer afternoon.
Under normal circumstances, these droplets roll down the coil and drip into a drain pan. From there, a PVC pipe called the condensate drain line routes the water safely outside or into an interior floor drain. A leak happens when this seamless process gets disrupted.
The top 4 reasons your AC is leaking water inside
When an air conditioning system begins dripping indoors, the issue almost always boils down to one of these four common culprits:
1. A clogged condensate drain line
By far, a blocked drain line is the number one reason an AC leaks indoors. Over time, the moisture moving through the PVC pipe creates a breeding ground for algae, mold, mildew and sludge. Dust and household debris can also settle inside the line.
When the pipe gets blocked, the water has nowhere to go. It backs up the line, overflows the drain pan and spills directly into your home, risking damage to ceilings, walls and flooring.
2. A dirty air filter
Many homeowners don’t realize that a simple air filter can cause a major water leak. When an air filter is clogged with dust, pet dander and debris, it restricts the volume of warm air passing over your evaporator coil.
Without enough warm airflow to balance the temperature, the cold refrigerant causes the coil to drop below freezing. The condensation on the coil turns to solid ice. When that block of ice eventually melts, the massive rush of water completely overwhelms the drain pan.
3. A damaged or rusted drain pan
If you have an older air conditioning system (typically 12 to 15 years old), your drain pan might simply be reaching the end of its lifespan. Older pans made of metal can rust out and corrode over time, while plastic pans can become brittle and crack.
Water drips perfectly off the coils but slips straight through the pinholes or cracks in the pan onto your floor, bypassing the drain line entirely.
4. Low refrigerant levels
Similar to a dirty filter, low refrigerant levels change the pressure dynamics inside the system. This drop in pressure causes the evaporator coil to become entirely too cold, causing the condensate to freeze on the coil before it has the opportunity to drain away, causing the coil to become plugged with ice.
Once the system shuts off or struggles to keep up with the summer heat, the heavy ice layer melts rapidly. Note: If you hear a gurgling or hissing noise alongside a drop in cooling performance, a refrigerant leak is highly likely.
Frequently Asked Questions
Can I still run my AC if it’s leaking water?
No, you should not run your air conditioner if it is leaking water inside. Turn off the system at the thermostat immediately to prevent structural water damage, mold growth and electrical hazards. Leave the system off until the root cause of the leak is diagnosed and repaired.
Why is my AC leaking water outside?
An AC leaking a small amount of water outside near the condenser unit is completely normal. This is just excess condensate being discharged from the properly functioning Condensate Drain system as it removes humidity from your indoor air. However, a large, continuous puddle or water pooling around the outdoor foundation could indicate a cracked drain pan or a malfunctioning condensate pump.
Call the pros at CJ Hansen
The absolute best way to prevent water leaks from happening in the first place is through regular, annual maintenance. A professional pre-season tune-up catches rusted pans, dirty coils and clearing drain lines before the summer heat hits the Willamette Valley.
If your air conditioner is making an unexpected splash, give our experienced team a call today at (503) 362-3643 or contact us online to schedule your AC repair. We’ll get your system running properly and keep your home cool, dry and comfortable.