AC Leaking Water Inside? Causes, Quick Fixes & When to Call

Your air conditioner doesn't just cool the air, it pulls moisture out of it. In San Antonio's humidity, that can be several gallons of water a day, and it's all supposed to flow out through a small drain line. When something goes wrong, the water ends up in your closet, attic, or ceiling.

1. Clogged Condensate Drain Line (Most Common)

Algae, sludge and dust build up inside the drain line until water can't get through. Many systems have a safety float switch that shuts the AC off when this happens, so a leak and an AC that won't turn on often go together (see AC not turning on).

What you can try: Find the PVC drain line near the indoor unit. Many have a cap or T-fitting where you can pour a cup of white vinegar to help break up buildup. Some homeowners use a wet/dry vac on the outdoor end of the line to pull the clog out.

2. Cracked or Rusted Drain Pan

Older systems, especially in attics, can have drain pans that rust through or crack. If the pan is damaged, it needs to be replaced.

3. Frozen Coil Melting

If your indoor coil froze, the melting ice can overwhelm the drain pan. Look for ice on the copper lines. See why your AC is frozen.

4. Dirty Air Filter

A clogged filter can lead to a frozen coil and then a leak. It's the cheapest fix on the list, change it regularly.

5. Disconnected Drain Line or Bad Installation

If the drain line came loose or the unit isn't sitting level, water may not flow where it should.

Preventing Drain Line Clogs

A yearly tune-up includes clearing and flushing the drain line. Our maintenance plan covers two visits a year so small clogs never turn into ceiling stains.