AC Leaking Water Inside? Causes and What to Do Right Now

In humid climates your AC pulls gallons of water out of the air on a summer day. That water is supposed to drain away through the condensate line. When it doesn't, it ends up on your floor or ceiling.

First steps

1. Turn the system off at the thermostat to stop producing more water.
2. Contain the water with towels or a bucket and move valuables.
3. If water is near electrical outlets or the ceiling is sagging, turn off power to that area and stay clear.

Common causes

• Clogged condensate drain line: algae and sludge are very common in the South.
• Tripped float switch: many systems have a safety switch that shuts the AC off when the pan fills. If your AC suddenly stopped and there's water in the pan, this may be why.
• Cracked or rusted drain pan
• Frozen evaporator coil: ice melts and overwhelms the pan. See frozen AC coil.
• Failed condensate pump in systems that pump water uphill or outside.
• Disconnected drain line or poor installation slope

What's normal

Water dripping from a small PVC pipe outside the house during cooling season is normal. Water inside around the air handler or furnace is not.

Prevention

• Change filters regularly to prevent freezing.
• Have the drain line flushed during annual maintenance.
• Ask your contractor whether periodic vinegar treatment of the drain access is appropriate for your system.
• Make sure a float switch is installed on attic units.

When to call

Call a licensed HVAC contractor if water keeps returning, the float switch keeps tripping, the pan is damaged, or you see ice on the coil or lines.

Safety first

Some HVAC checks are safe for any homeowner: the thermostat, the air filter, a single breaker reset, and keeping the outdoor unit clear. Others are not. Leave refrigerant, capacitors, wiring inside the unit, and anything involving gas to a licensed professional. If you ever smell gas or see smoke or sparks, leave the home and call 911 or your gas utility from a safe place.

More guides

• Why Is My AC Blowing Warm Air? 8 Causes and What to Check
• AC Repair vs. Replace: How to Decide
• How Often Should You Change Your AC Filter?
• AC Frozen? What Causes Ice on the Coil and What to Do

This article is general information, not professional advice or a diagnosis. Always consult a licensed HVAC contractor about your specific system.