How to Fix a Window AC Unit That's Dripping Water Inside Your Home

A window AC dripping inside is usually caused by a clogged drain, improper installation angle, or dirty evaporator coils that need cleaning or repositioning.

  1. Kill the Power First. Safety first. Switch off the unit and unplug it from the wall outlet. Let it sit for at least 30 minutes to allow any ice buildup to melt completely before you start working on it.
  2. Angle It Backward. Window AC units must tilt slightly backward toward the outside to drain properly. Use a level to check if your unit slopes at least 1/4 inch toward the exterior. If it's level or tilting inward, you'll need to adjust the mounting brackets or add shims under the front edge.
  3. Unblock the Drain. Find the small drain hole on the bottom of the unit, usually toward the back. Use a thin wire, pipe cleaner, or small screwdriver to gently clear any debris, dirt, or algae blocking the hole. You might see water start flowing out once it's cleared.
  4. Purge the Coils. Remove the front panel and filter to access the evaporator coils inside. Spray them with AC coil cleaner or a mixture of warm water and mild dish soap. Let it sit for 10 minutes, then rinse with clean water from a spray bottle. Dirty coils create excess moisture that can overwhelm the drain system.
  5. Refresh the Filter. A clogged filter restricts airflow and causes ice buildup that melts into excess water. If you have a disposable filter, replace it. For washable filters, rinse thoroughly with warm water and mild soap, let it air dry completely before reinstalling.
  6. Empty and Sanitize. Look for the removable drain pan underneath the evaporator coils. Pull it out carefully and empty any standing water. Wash it with soap and water to remove algae or mold that might cause clogs. Make sure it's properly seated when you put it back.
  7. Confirm the Fix. Reassemble everything, plug the unit back in, and run it for several hours. Monitor closely for any new dripping. The condensation should now flow outside where it belongs rather than into your room.