AC leaking water
easy 20–45 min
Tools: wet/dry vacuum, flashlight, bucket, stiff wire · Materials: replacement air filter, condensate tablets
Steps
- Switch the system off at the thermostat so the leak stops growing while you work.
- Find the condensate drain line — a PVC pipe leaving the indoor unit — and its outside end; put the wet/dry vacuum over the outside end and run it for two minutes to pull the clog out.
- If the drain pan under the unit is full, empty it and check the pan for cracks or rust.
- Replace a dirty filter; ice forming and melting on the coil floods the pan.
- Pour a cup of distilled white vinegar into the drain line's access tee every month in cooling season.
Stop and call a pro if
- the pan is cracked or rusted through
- the coil is iced over and stays iced after the filter change and a few hours of thawing
- the leak is from a refrigerant line rather than the drain (oily residue, hissing)
- the unit is in an attic and the ceiling below is stained
What a pro does that you can't
An HVAC technician flushes the drain line under pressure, replaces a corroded pan or a failed condensate pump, and installs a float switch so an overflow shuts the system down instead of the ceiling.
DIY cost: $0–15 for vinegar and a filter