Water around the indoor unit: a clogged condensate drain
The AC pulls water out of the air all day and sends it down a small drain line. When the line clogs, the pan overflows onto the floor, the ceiling below, or the furnace electronics. The EPA's rule for anything it soaks is to dry it within 24 to 48 hours to prevent mold.
What is probably happening
- Algae or sludge blocking the condensate line, the most common cause. Carrier lists water pooling near the indoor unit and a system that shuts itself off (float switch) as the signs.
- A rusted-through drain pan, or a failed condensate pump if the unit is in a basement.
- A frozen coil that is now melting, if the unit was blowing warm before the water showed up.
Do this in the next five minutes
- Thermostat to OFF. Mop up and get towels under the unit.
- Find where the drain line exits outside, usually a PVC pipe near the outdoor unit. Hold a wet/dry vacuum on the end for a minute to pull the clog.
- Indoors, find the capped tee on the drain line near the coil. Pour a cup of distilled vinegar in. Do not use bleach; it damages some pans and pipes.
- Set to COOL and watch for water dripping at the outside end. If the pan drains and the floor stays dry, you fixed it.
- Move anything wet off the floor and run a fan on it. If drywall or carpet is soaked, see the water damage path.
Do not
- Do not blow compressed air into the line from inside. It can blow the pan joint apart.
- Do not bypass or unplug the float switch to get cooling back. It is the only thing stopping the next overflow.
- Do not leave a wet ceiling or carpet for the weekend. Past 48 hours the bill becomes a mold job.
Who to call
A licensed HVAC technician, if the vacuum does not clear it
An HVAC technician clears the line, replaces a rusted pan or a failed pump, and adds a float switch if there is none. A plumber does not work on the air handler.
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What it should cost
$75 to $200
AC drain line cleaning, national range
Source: Angi, HVAC repair cost, updated August 2026. View source
National published range, not a quote for your job. The full cost table for this trade is on the hvac page.
Ask this contractor, on the phone, before anyone comes out
Tap each one as you ask it.
- Is there a float switch on this system, and if not, will you add one?
- Is the drain pan rusted or cracked, and is the pan a separate line item?
- Is the line sloped and trapped correctly, or will it clog again?
- Does the coil look dirty or iced, which could be why it made so much water?
End the call if
- A coil or system replacement quoted for a clogged drain.
- A drain cleaning bill far above $200 with nothing else done.