I discovered a leak under my bathroom sink. There are two sinks in the bathroom with the same plumbing set up and only the one side is leaking. The water is coming from the marvel connector on the pipe coming out of the wall. The connector is 1-1/2 in.

There are just bare threads on this connector - no nut or anything... Is that even a viable setup or did someone cut corners when installing this? The red arrow shows where the water is leaking from.

the culprit

enter image description here

Does this seem like an easy fix? I've noticed a bad smell coming from the pipes once in a while and that's leading me to question the entire setup. I'm wondering whether I can just slip a nut on there or if I'll need to replace the whole P trap.

Any tips or guidance would be much appreciated.


  • Hilariously bad install. Those are hand tighten connectors so you should be able to take it apart easily to make sure they didn't caulk that pipe in or something to deal with the sealing problems.
    – K H
    Apr 15, 2021 at 2:20
  • Not only, but also, that gray nut at the top is crooked.
    – Jasen
    Apr 16, 2021 at 11:28

3 Answers 3


What is missing on this setup is the compression nut. It should fit over your 1 1/2 inch drain pipe going into the wall stub. When you tighten it down the inner gasket will seal around the drain and prevent water and odor from escaping into the room.
This looks like a poor diy job. The problem may have been that the bend in the drain pipe before the Marvel connector prevents the nut from properly threading on the connector. Regardless, you need that compression nut on there. You can pick one up from any home supply or plumbing store. You may have to buy the entire connector. You're also going to have to play with the P trap to get it properly aligned so the nut will thread on. There is play in the pipes. As a last resort you may have to buy a longer 90 degree drain section coming out of the P trap and rotate the P trap 90 degrees toward the front of the sink to get a straight shot into the stub.


It's an easy fix. There should be a compression washer and nut on that slip joint. It's hard to see but it looks like the drain tube is small for that fitting and will require a suitable washer or an adapter.

And it looks like the trap is too close for the compression nut to fit properly so you may need to turn it 90 degrees towards the front of the cabinet. And then it may be too short so you may need a new longer arm for the P trap.

The good news is you can buy a kit that will replace the whole thing correctly and they are cheap. This should be a very easy no-tools repair.

Here's an example of what you could pick up and I've highlighted the bits you actually need

enter image description here


If they had cut the pipe back a bit closer to where it comes out of the wall, they would have had straight pipe to tighten the compression fitting on and everything would have worked. Suggest getting a new reducing fitting and correct glue, using a hacksaw blade to cut the pipe back a few inches and gluing the new fitting on. Everything should tighten up just fine.

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