Why is water dripping from my furnace when AC is on?
When the air conditioner runs, water drips directly from the furnace and pools on the ground. This unexpected leaking forces people to constantly mop up standing water and manage basement moisture.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1Checking previous posts for similar issues
- 2Assuming it is normal condensation
- 3Clearing clogged condensate drain lines
- 4running the dehumidifier
- 5mopping up the pooled water
- 6checking and resetting the condensate pump breaker
- 7replacing or installing a proper P-trap
- 8cleaning clogged vinyl tubing
- 9Placing plastic containers under the leak as a precaution
In their words
Unedited, most upvoted first, each linked to the thread it came from.
“water started coming from the furnace in the last month or so. Do I need to call an HVAC technician or is this something I should be able to fix myself?”source ↗
“yesterday I noticed a fair amount of water on the ground and I see water dripping from my furnace(see picture) when the AC is on.”source ↗
“We’ve lived in our 1920s Philly row home for just over a year. Our basement definitely has some moisture, but we’ve never had any pooling or leaking water. We went away for a few weeks and came home to this (we had a house sitter staying at the house who had mentioned some water pooling and was running the dehumidifier and mopping it up).”source ↗
Where this came up
People with this problem also raised
- 3Why is there water on the floor around my new water heater?
- 4Water spitting out of pump vent pipe
- 2Why is cold air blowing out of my AC drain line?
- 4Water leak from screw after flushing water heater
- 2Water leaking behind new gutters and soffits
- 3Refrigerator stops cooling properly after being moved on its side