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Water dripping from the indoor AC unit: what to check

Your air conditioner pulls moisture out of the air and drains it away through a small pipe. When that path clogs, the water ends up on the floor.

Before you start: Turn the system off at the thermostat, and switch off the unit's power before opening any panel.

What to check first

  1. The air filter

    A clogged filter can make the coil freeze. When the ice melts, it overwhelms the drain pan. Replace the filter if it is dirty.

  2. The condensate drain line

    Find the PVC drain pipe near the indoor unit. Many have a capped access port: flush it with a cup of white vinegar or water, or pull the clog out from the outside end with a wet/dry vacuum. Avoid bleach, which can damage some pans and pumps.

  3. The drain pan

    Look for standing water, rust or cracks in the pan under the coil.

  4. The condensate pump

    If your unit has a small pump box, make sure it is plugged in and its float is not stuck. A pump that runs but moves no water needs replacing.

  5. Ice on the coil

    If you see ice on the coil or the refrigerant lines, turn cooling off and run the fan to thaw it, then see the guide to ice on the AC line.

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Parts you may need

  • HVAC air filterThe size is printed on the frame of the old filter.
  • Condensate drain line tablets or cleanerHelps keep the line from clogging again.
  • PVC drain line fittingsCondensate lines are usually 3/4 inch. Only if a fitting is cracked.
  • Condensate pumpOnly if yours has failed. Match the voltage and outlet size.

Tools

  • Wet/dry vacuum
  • Flashlight
  • Towels

Call a licensed pro if

  • The drain pan is cracked or rusted through
  • The coil keeps freezing after you replace the filter
  • Water is reaching electrical parts or a furnace below the unit

General guidance, not professional advice. Parts differ by brand and model, so check yours before buying. Aisle numbers and prices in the app are estimates. How Ask Danny uses AI. Updated September 16, 2026.

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