AC leaking water inside the car

Symptoms

• Water on the floor, usually passenger side, when AC has been running
• Wet or damp carpet smell developing over time
• No leak noticed when AC is off
• Sometimes accompanied by a musty smell

Likely causes

• CommonClogged evaporator condensation drain tubeNormally this tube drips water harmlessly under the car; when clogged with debris, water backs up and overflows into the cabin instead.
• PossibleDisconnected or misrouted drain tubeIf the tube has come loose or shifted, condensation can drip into the cabin instead of outside.
• Less commonEvaporator housing cracked or damagedPhysical damage to the housing can let water escape into the cabin regardless of drain condition.

What to do

1. Confirm the leak only happens with the AC running (not rain or a different water source), by testing the AC on a dry day with the car stationary.
2. Look under the car near the firewall for a small drain tube that should be dripping water while the AC runs; if it's dry while water pools inside, the drain is likely clogged.
3. Carefully use a length of wire, a zip tie, or low-pressure compressed air (from the drain hose end) to clear a blockage in the drain tube, following a guide for your model.
4. Run the AC afterward and confirm water is now dripping outside under the car instead of pooling inside.
5. Dry out any wet carpet or padding thoroughly (fans, desiccant, or removing carpet if needed) to prevent mold growth from the accumulated moisture.
6. If clearing the drain doesn't stop the interior leak, have the evaporator housing and drain connection inspected for damage.

Tools and parts

• Wire or zip tie
• Wet/dry vacuum (for cleanup)

When to call a pro

See a mechanic if you can't locate or clear the drain tube yourself, or if water continues leaking inside after clearing it, since the evaporator housing itself may need inspection.

Safety