What Do I Do If My AC Drain Line Is Clogged?
Switch off the AC, soak up the water, and check the drain pan and the line's outside end. Many lines have a cleanout where you can flush with water or a little vinegar. If it stays blocked, request a technician.
Request an HVAC technicianHow the drain works
As air passes over the cold indoor coil, moisture drips into a pan and runs outside through a small pipe.
Why it clogs
Algae and slime grow in the warm, wet line, especially in a climate this humid, where the AC removes gallons of water a day.
Signs
Water around the air handler, a wet ceiling under an attic unit, a musty smell, or a system that shuts off because a float switch tripped.
Clearing it
Switch the system off. Find the cleanout tee near the indoor unit, remove the cap, and flush slowly with water. A wet-dry vacuum on the outside end can pull out a clog.
Preventing it
Flush the line every few months in the cooling season and have it cleaned at each tune-up.
When it's more
Overflowing pans in attics can ruin ceilings. If the pan is rusted or cracked, have it replaced. See AC repair.
Float switches
Many systems have a float switch in the pan or line that shuts the AC off before water overflows. If yours keeps tripping, the line is the cause, not the switch.
Attic units
An air handler in the attic should sit in a secondary pan with its own drain or switch. If yours doesn't, ask about adding one.
Use the right cleaner
Plain water or a cup of white vinegar is enough for regular flushing. Avoid bleach in lines with metal parts or a pump, and never pour anything into the line while the system is running.
More HVAC guides
Need AC or heating help in Lake Charles?
Send a request and a HVAC technician will get in touch. Requests answered 7 days a week.
Request an HVAC technicianPrefer email? [email protected]