Water leaking from an AC is usually caused by a clogged condensate drain, a dirty filter, or a frozen coil. Clean the drain line or call a technician.
Common causes
- Clogged condensate drain line.
- Dirty air filter.
- Frozen evaporator coil.
- Cracked drain pan.
- Low refrigerant.
- Poor installation.
Fixes
- Clear the drain with a wet/dry vac or vinegar.
- Replace the filter.
- Let a frozen coil thaw.
Prevention
Replace filters every 1 to 3 months.
Call a pro
If water persists.
Source of the leak
Water from an AC usually comes from a clogged condensate drain line, a frozen evaporator coil that melts, a dirty filter, a cracked drain pan or low refrigerant. An AC removes humidity, producing several gallons of condensate per day in humid weather, which flows out through the drain line.
- Algae and sludge clog drain lines, especially in warm, humid conditions.
- A dirty filter restricts airflow and causes the coil to freeze.
- Window units need a slight tilt to the outside, so water drains out.
Fixes
Turn off the AC. Replace the filter, clear the drain line with a wet/dry vacuum, and pour a cup of 50/50 water and vinegar down the line every few months. Check the drain pan for cracks. Call an HVAC technician for refrigerant leaks, ice buildup that returns, or water near electrical components. A float switch can shut the system off before overflow, and many codes require one.
Source of the leak
Water leaking from an AC unit is often a clogged condensate drain line, a dirty filter that freezes the evaporator coil, low refrigerant, or a cracked drain pan. A home AC can remove several gallons of moisture a day in humid weather.
Fixes
Turn off the system, replace the filter, clear the drain line with a wet vacuum, or pour a cup of vinegar into the line. Persistent leaks need an HVAC technician. Ignoring leaks can cause mold and ceiling damage.
Condensation and drain issues
An AC removes about 5 to 20 gallons of water a day from air in humid weather through the evaporator coil, and this drains through a condensate line. A clogged drain line due to algae is the most common cause of leaks, followed by dirty filters causing coil freezing. Window units drip outside by design, and tilt the unit slightly toward the outside.
Maintenance details
Flush the drain line every 3 months with a cup of 50/50 vinegar and water. Install a float switch to shut the system off when the pan fills. Check the insulated refrigerant line. A frozen coil indicates airflow or refrigerant problems. Water damage from leaks can cause mold within 24 to 48 hours.
Based on data from the US Department of Energy and ENERGY STAR
