We installed new vanity and the drain pipe (floor) and sink pipe don't line up to install S-trap. We worked around it by installing a straight pipe but now we are getting smell coming from sewer gas. I tried to re-install S-trap and still can't get it to fit all the pieces.

The holes are off by ~0.5 inches. Home depot recommended that I use flexible pipe but some forums have recommended not to use flexible pipe as it causes issues down the road.

What can I use to work around this problem? I'm lost after trying multiple things. Thank you for your help.

this is what I've put together so far. Want to avoid using the flexible pipe if possible.

  • I think it is to challenge the plumber's skill in heating and bending a straight PVC pipe to an S curve with 0.5" offset. It is doable/easier with a long pipe, then cut to fit.
    – r13
    Jun 8, 2021 at 14:02
  • Have you tried using teflon tape? it's standard to use that to seal up the connection between the threads instead of only relying on the rubber seal. Apply a generous amount, at least 5 wrap-arounds on the threaded side.
    – Nelson
    Jun 8, 2021 at 14:23
  • There's no rubber seal in a compression fitting. Their may be a nylon gasket, but often it's just plastic. Putting tape on the threads would only deal with one side of the situation. I would not do that.
    – isherwood
    Jun 8, 2021 at 14:53
  • The instructions always say to hand tighten the trap nuts. I have always had to get a pair of Chanellocks and tighten those nut about a quarter turn after being hand tightened.
    – JACK
    Jun 8, 2021 at 16:19

1 Answer 1


It looks to me like there's plenty of available swing in your trap assembly to get better alignment. Swing the trap U around to the back and bring the other bend forward. Try various positions until you find one that works.

The leak is because the nut isn't tight enough. There's no magic to these things--just get a channel-lock pliers on it and give it another half turn. Unless you have it cross-threaded or there's gunk in the way it'll close up.

As for the sewer gas... this is why S-traps are illegal. The momentum of the water creates a vacuum which pulls the plug out of the trap, leaving you with no seal. You should look into an air admittance valve (AAV) to break the vacuum. Those aren't usually legal either (because they can leak in cases of a clog where the drain comes down from a higher level), but it's better than stink.

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