What is this extra pipe dripping into my sink drain?
The extra dripping pipe is an HVAC condensation drain line routed into your household plumbing. When it leaks or drips continuously, it usually points to a clog or blockage in the outflow line that prevents proper drainage.
What the numbers show
Counted from the threads quoted below. How we count
- The most recent one is from October 2026.
- This comes up 21.2× more often in r/hvacadvice than across the site as a whole.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
Found another way around this?
Share your steps and trade-offs so fellow engineers don't have to reinvent the wheel. No account required.
- 1Moving the hose clamp closer to the end of the hose and tightening it downDid this help you?
- 2Clearing a potential clog in the lineDid this help you?
- 3Turn off the AC so it stops drainingDid this help you?
- 4Put a bucket under the dripDid this help you?
- 5Use a line blower from Home DepotDid this help you?
- 6Suck the line out with a shop vacDid this help you?
- 7Adding a T vent to help with head pressureDid this help you?
- 8Shortening the tube at the pumpDid this help you?
- 9Replacing the tube with 3/4 inch PVC and installing a trapDid this help you?
- 10Running PVC pipe along the ground from the cut-back drain line to a flower bedDid this help you?
- 11route the pipe to an indoor drain or install a condensate pumpDid this help you?
- 12attach a PVC pipe extension to direct water to the lawnDid this help you?
- 13remove stones, add gravel, and pipe the line directly into the groundDid this help you?
- 14Replacing the barbed connector or gluing a new style of PVC pipe above itDid this help you?
- 15Turning off the thermostat and the entire unit to let it restDid this help you?
- 16Checking the attic drip pan and drain lines manuallyDid this help you?
- 17using a makeshift trash bag and bucket contraption to catch condensate overflowDid this help you?
- 18Making a DIY loop out of vinyl tubing to act as a makeshift trapDid this help you?
- 19Buying a proper manufactured condensate trap replacement partDid this help you?
- 20Hiring a technician to install an official trapDid this help you?
- 21Using paper towels to absorb the leak and changing them out when they become soggyDid this help you?
- 22Checking and changing the air filter more frequentlyDid this help you?
- 23Attempting to clear out gunk from the pipe and furnace part using an aquarium brushDid this help you?
- 24Considering applying PVC primer and glue to secure the unglued pipe fittingDid this help you?
- 25reinserting the hose back into placeDid this help you?
- 26checking the pump by pouring water into itDid this help you?
- 27monitoring the area to see if the hose pops out againDid this help you?
- 28Flushing the line with vinegarDid this help you?
- 29Clearing the line with a wet/dry shop vacuumDid this help you?
- 30Hiring HVAC technicians for chemical and pressure flushesDid this help you?
- 31Installing an air admittance valve or pipe extensionDid this help you?
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“Old ac was replaced recently. I added the T vent cause the drain pan wasn’t draining due to head pressure caused by the other end sitting in water at the pump.”source ↗
“I’ve been checking the blue plug occasionally and noticed some water collecting.”source ↗
“Prior owners installed pavers around the side of the home, causing the AC drain line to drain directly onto the pavers.”source ↗
“Over time this seems to have caused the pavers to shift and you can see in the middle of the photo where the water collects. The pavers are also becoming mossy.”source ↗
“I want to address it but am not sure of the best solution.”source ↗
“This hose was dripping water on the floor. It looks like it just popped out of the hole, but putting a dripping hose in the wrong hole seems like a bad idea.”source ↗
“This L-shaped PVC pipe is high up on the exterior wall of my house and I noticed water dripping from it.”source ↗
“Is this likely the secondary/emergency condensate drain from the AC coil? If it’s dripping, does that usually mean the primary condensate line is clogged and I should check the drain pan?”source ↗
“I’d say about a gallon or 2 of water has been dripping from this for the past 2 hours or so.”source ↗
“Moved into a brand new house beginning of 2025 a month after living in it I did a vinegar flush. Left it in the condensate line for 30 minutes then shop vacuumed the drain line. This led to multiple clogs over the next few months.”source ↗
“AC worked with no clogs for almost a year. Did a vinegar flush about a week ago and since I been watching it after I had to shop vacuum it 3 times.”source ↗
“Due to seeing a clog almost happening through the t pipe. You could see water flowing back and forth and gurgling in the pipe about 3/4 full.”source ↗
“Having trouble with the end of our AC drain line.”source ↗
“The white top piece (Picture 2) has come loose and won’t properly sit/reseal on the black pipe (Picture 3).”source ↗
“Because the pipe isn’t sealing, the water is just pooling around the base of the black pipe (Picture 4).”source ↗
“A couple of weeks ago my HVAC suddenly stopped working.”source ↗
“A few days ago I noticed water dripping from our window and went to look outside and noticed the water was coming from a drain in the gutter.”source ↗
“I noticed no water in the drip pan beneath the HVAC but the pipe highlighted in blue had condensation and from the video you can see water trying to push out.”source ↗
“According to the manual for this unit, it states there should be a p-trap since the pressure is negative, but you can see there isn’t one.”source ↗
“Does this hold up, or am I cray cray and need a technician to come for an actual trap installation?”source ↗
“I thought I was going crazy cause to me that looks like shit.”source ↗
“I hate it but it's probably fine. It will possibly get flagged on a pre sale home inspection.”source ↗
“Around mid summer I noticed that the AC condensation pipe was leaking water right where that white hexagon screw meets the furnace.”source ↗
“The PVC pipe isn't glued, we were able to take it apart and clean some gunk out with an aquarium brush within the pipe and within the furnace part, but it's still leaking at that hexagonal white part.”source ↗
“He basically said not to worry about it until I replace the furnace and/or AC.”source ↗
“The leak still being there doesn't seem right to me, but I wanted to get some 2nd opinions.”source ↗
“Yes it’s fine where you have it. Is that coming from a humidifier?”source ↗
“Id say more like pushed out. You did the right thing by putting It back.”source ↗
“Prior owners installed pavers around the side of the home, causing the AC drain line to drain directly onto the pavers.”source ↗
“Over time this seems to have caused the pavers to shift and you can see in the middle of the photo where the water collects. The pavers are also becoming mossy.”source ↗
“I want to address it but am not sure of the best solution.”source ↗
Where this came up
People with this problem also raised
- 126How to fix a leaking water pipe in a tight space
- 2Why does my evaporator coil drain outside instead of the bathroom?
- 2Why does my AC drain line keep backing up and leaking?
- 43How to clear a clogged AC condensate drain line
- 3How to tie in a vent line and shower drain in tight spaces
- 4How to fix a sink drain without removing the P-trap