AC leaking water

Your AC makes water on purpose. Warm, humid air crosses the cold indoor coil, moisture condenses and drips into a pan, then runs out a drain line. On a humid Tampa day a home system can pull several gallons out of the air. A leak means that water isn't making it out.

Do this in the first hour

1. Turn the system off at the thermostat. That stops more water forming. If water is near the air handler's wiring or an outlet, switch it off at the breaker too.
2. Soak up the water. Towels, a wet-dry vac, a fan. Move anything that can stain or warp.
3. Check the drain pan under or inside the air handler. A full pan means the drain line is clogged. A dry pan with water elsewhere points to a cracked pan, a loose fitting or a frozen coil melting.
4. Check the ceiling. If the air handler is in the attic, look for brown rings or soft drywall below it. Take photos for your records or your insurer.

Why ACs leak

A clogged drain line

The most common cause by far. The drain line stays warm, dark and wet, so algae and sludge grow inside it. Florida humidity makes this routine rather than rare. When the line backs up, the pan overflows.

Most systems have a cleanout: a capped T-fitting on the drain line near the air handler. You can often clear a mild clog with a wet-dry vac at the outdoor end of the line, where it leaves the house. Many techs suggest pouring a cup of white vinegar into the cleanout every month or two to keep algae down. Check your system's manual first, since some manufacturers list what not to use.

A tripped float switch

Many systems have a float switch in the pan or drain line that cuts power when water backs up. It stops the overflow, and it also stops the cooling. Clear the drain and the switch usually resets. Florida's mechanical code requires a secondary pan or float switch on new installs where an overflow could damage the home. If your attic unit has neither, ask a tech to add one.

A rusted or cracked pan

Older metal pans rust through, so water ends up under the unit even with a clear drain. A pan can sometimes be replaced on its own. On some units it's built into the coil.

A frozen coil melting

If the coil ices over from a dirty filter or low refrigerant, the ice melts when the system cycles off and can overwhelm the pan. If you see ice too, read AC not cooling.

A failed condensate pump

Air handlers in closets or garages with no downhill drain use a small pump with a tank. If it fails, water backs up fast. You'll usually find it next to the unit.

The mold question

Water that sits is how mold starts. The EPA's guidance is to dry wet building materials within 24 to 48 hours to prevent mold growth. In a Tampa attic or wall, warm and damp most of the year, that window matters.

A small damp spot you caught early and dried is usually fine. Get it looked at if:

• Drywall is soft, sagging, or stained in a ring that keeps growing.
• You smell must after the area has dried.
• The leak ran for days before you found it.

An AC company fixes the source. Mold in drywall or insulation is a separate job, usually for a water damage or mold company. Florida licenses mold assessors and remediators, so ask for the license there too.

If you rent

Tell your landlord or property manager in writing the same day, with photos, and leave the system off until someone looks at it. Who pays and how fast depends on your lease. A written report protects you if the damage spreads.

Leak questions