My plumber attached my shower area drain and the WC (water closet, i.e. toilet) drain through a single pipe and installed a P-trap at shower drain. The level of the P-trap is such that when we flush the WC some of its water runs into the shower area drain P-trap and it starts emitting a foul smell in the bathroom.

I believe he has installed these drains with a T-joint instead of a Y-joint and level of pipe is not correct as water runs backwards to the shower drain.

Is there any solution to it without damaging the bathroom tiles and floor?

  • Is your bathroom on the ground floor? Second floor? Do you have any method of getting underneath the plumbing? Sep 23, 2015 at 13:44
  • 5
    There probably isn't a way to repair this unless the pipes are in a unfinished space underneath. The plumber should be the one to fix this.
    – paulmz
    Sep 23, 2015 at 16:36

1 Answer 1


From your description it doesn't sound like you are actually seeing sewer waste water emitting from the shower drain, but you do smell sewer gas in the shower area. Most likely you have a drain ventilation problem. When the toilet is flushed, the water entering the drain displaces the air that's already in the drain pipe. If the pipe doesn't have sufficient ventilation it will push the stinky air out of the easiest opening (your shower drain).

  • 1
    Yeah, whatever "plumber" did this work needs to be whacked over the head with a wet vent a few times -- because that's what he messed up. Nov 24, 2015 at 3:16

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