AC Leaking Water

Water leaking from your AC indoor unit or dripping from the ceiling below an attic-mounted air handler is almost always a condensate drain problem. Your AC produces 5–20 gallons of water per day in summer — that water has to go somewhere. When it can't, it overflows. Here's what's happening and what to do this minute.

Most Likely Causes

1. Clogged condensate drain line (most common)

Algae and biofilm build up in the 3/4-inch PVC drain line. When fully blocked, water backs up into the secondary pan and eventually overflows. Symptom: water dripping from the air handler, or worse, water spots on the ceiling below an attic unit.

2. Tripped float switch (good news)

If your system has a float switch, it should have killed power before water overflowed. If your AC isn't running AND there's water in the pan, the float did its job — but you still need to clear the drain.

3. Rusted-through condensate pan

Older systems develop pinhole rust in the condensate pan. Water drips through. Requires pan replacement.

4. Frozen evaporator coil thawing

If the coil froze and you turned the system off, the ice melts and dumps several gallons of water. The drain may not be clogged — it's just overwhelmed.

5. Disconnected drain line

If the drain line came apart at a coupling, water dumps wherever the broken end is — often inside the air handler closet or attic.

Try These Steps Before You Call

• Turn off the AC immediately to stop more water from accumulating.
• Find the condensate drain line — usually a 3/4-inch white PVC pipe exiting your air handler closet or running through the attic.
• If you have a wet/dry vac, attach it to the outside termination of the drain line and pull suction for 60 seconds. Often clears the clog instantly.
• Pour 1 cup of distilled white vinegar into the drain access point at the air handler (the T-fitting with a removable cap). Wait 30 minutes.
• If those don't work, call us — full clearing requires nitrogen pressure or a wet vac with a proper adapter.

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