Why is a newly installed sink drain leaking above the trap?
Leaks directly above the P-trap on a new vanity usually stem from loose slip-joint nuts or worn, misaligned rubber gaskets. This allows water to escape during use, which risks water damage to the cabinet below until the connections are properly tightened or the washers are replaced.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1Tightening the nut
- 2Using the correct sized washer or adapter
- 3Calling the installer back to fix it under warranty
- 4Replacing only the gaskets and PVC washers instead of the entire pipe assembly
- 5Using plumber's putty instead of or along with the rubber gasket to seal the drain assembly
- 6considering using superglue
- 7looking into learning plumbing basics from books
- 8Loosening everything, ensuring the connection sits flush, and tightening the section first
- 9Trimming the tailpiece and flipping the p-trap around so the slip side ends up on the sink side
- 10Extending the trap arm in the wall and flipping the trap to the correct side
- 11Ensuring gaskets are seated properly and tightening down with a wrench
- 12Buying a different cheap drain kit from a hardware store
- 13Running some water in the unused sink bowl occasionally to prevent sewer gas odors from dry traps
- 14Leaving the current setup as is since it still works in most cases
- 15trying drain cleaner
- 16taking apart compression fit pieces manually
- 17inspecting vertical waste pipes with an endoscope
In their words
Unedited, most upvoted first, each linked to the thread it came from.
“I know very little about plumbing except I really don't want to do it.”source ↗
“Recently remodeled the kitchen, a "kind of" plumber told me this is wrong. There shouldnt be 2 p-traps and the rubber Y shouldnt be there... what is wrong here and what should it look like? And worst case what would happen if i leave it lile this”source ↗
“Ok gotcha but other than maybe not being up to code, is there anything that can happen down the road if i leave it?”source ↗
“At first, the drain was draining away very slowly and I thought it was a blockage.”source ↗
“now it refuses to drain at all.”source ↗
“My brother just got this new sink/vanity installed and it’s leaking from the drain above the trap.”source ↗
“Water damage on the new vanity.”source ↗
“I need to replace the middle two pipes(the two pipes above the copper p trap), the rubber gaskets are very old and the pipes are leaking.”source ↗
“Should I just replace the gaskets with new ones and new pvc washers?”source ↗
“What are my DIY options?”source ↗
“I think i need books and plumbing 101”source ↗
“When I took the drain plate off, I noticed what seemed to be a rubber gasket of some kind under it, but it was crumbling apart.”source ↗
“I went to my neighborhood Ace and got a gasket that fit the drain (pictured above) and then screwed it back in. But now when I fill the sink up to scrub some dishes, it does not hold the water.”source ↗
“Can anyone advise me on what I need to make it watertight?”source ↗
“Should I leave that black rubber gasket on? Or does the plumber's putty replace the gasket?”source ↗
Where this came up
People with this problem also raised
- 5Does every sink need a P-trap?
- 6Why is water backing up into the sink when appliances drain?
- 3Why does my sink drain keep clogging up?
- 4Why is my brand new kitchen sink draining so slowly?
- 3Why does my basement sink gurgle when the kitchen sink drains?
- 8Can you fix a cracked or broken kitchen sink yourself?