Water in rear footwell only when AC is running
Water is pooling in the rear passenger footwell specifically after driving with the AC on, rather than from rain or a leaking heater core. This buildup is likely caused by a clogged AC drain that prevents condensation from escaping properly, stopping drivers from figuring out the source without checking their air conditioning system.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1Vacuuming the water out repeatedly
- 2Checking and cleaning sunroof or cowl drains
- 3Inspecting the heater core and coolant levels
- 4Checking door drain holes and the AC evaporator drain
- 5finding your AC drain and shoving something up there to unplug the inevitable mud dobber nest or whatever that's up there
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“I was told by repair shop heater core was leaking but my heat works fine and my windshield doesn’t get foggy”source ↗
“I thought was my coolant at first cause my coolant is orange”source ↗
“Yes but I don’t see any water coming in it rain all night and was dry in morning but after driving it came back”source ↗
“According to my research it's most likely due to the AC clogging up. I only notice it when I run the AC as well. Just need confirmation. How big of an issue would this be? Is it an immediate fix? Can I do it on my own?”source ↗
Where this came up
People with this problem also raised
- 4Water pooling in window tracks even after cleaning weep holes
- 2Why is there standing water in my shower drain?
- 2What to check after hitting a deep pothole or road dip
- 2Why is my car making a weird noise after driving through water?
- 10Standing water in basement foundation plumbing cutout
- 3Do I have to strip my car interior if it rained inside?