Why Is My Air Conditioner Causing Water Damage?

A clogged condensate drain line is the most frequent culprit. Dust, mold, or algae can block the tube, causing water to back up and overflow the drain pan. The overflow then drips down the unit, soaking drywall, carpet, or wood floors.

An unlevel air conditioner also causes water to pool and spill. The unit needs a slight tilt toward the drain outlet. If the tilt is wrong, water sits in the pan and eventually overflows. A dirty air filter reduces airflow, causing the coils to freeze and then melt, producing excess water.

• Check the drain line for clogs
• Look for a tilted or unlevel unit
• Inspect the air filter for dirt
• See if the drain pan is cracked
• Look for ice on the coils
• Check the condensate pump if you have one

Start by turning off the air conditioner and unplugging it. Clean the drain line with a stiff wire or a wet-dry vacuum. Check the drain pan for cracks and replace it if needed. Make sure the unit sits level, with a slight tilt toward the drain.

Change or clean the air filter regularly, as a dirty filter can cause ice buildup. Inspect the coils for frost and let them thaw if frozen. Keep the area around the unit clear of dust and debris. In humid regions, consider these steps during the summer months.

Regular maintenance can stop water damage before it starts. Clean the drain line and pan at least once a year. Replace the air filter every one to three months, depending on use. Keep the area around the unit clear of debris and check the tilt seasonally.

During humid weather, run the air conditioner more often to keep coils from freezing. If you have a condensate pump, test it regularly. Also, check the drain line for kinks or blockages. A little prevention goes a long way in protecting your home.