I recently replaced my bathroom sink and the new drain pipe isn't threaded like the older one. So instead of a connection to the P trap with a threaded male/female piece and a tightening ring, the new drain simply slides into the P trap piece. This is where the leak is happening. I tried to use silicone to seal the open space but if running the water on a higher pressure, or if soap is used, the leak is immediate. What is the best way to eliminate the leak? Help! enter image description here

Note: Both new and old piping is PVC.

  • Best way to eliminate the leak is use the right size pipe. I believe there may be an adapter to mate the two different size pipes. Someone will post what piece you need to correct this, in addition it's not lined up very well. Mar 13, 2019 at 13:34

2 Answers 2


These compression fit plumbing pieces need to fit together very straight to get a good seal. Try to adjust all the joints to be as straight as possible. Because each joint can either slide or rotate, this is normally possible to do without much effort.

Also, many bathroom sink drains use 1 1/4" pipe, but many P traps and the pipes coming out of the wall are 1 1/2". It's a small difference, but it matters to make a proper seal. Most P-trap kits these days come with an adapter washer that is thicker than the normal 1 1/2" washer. It may have gotten lost in the packaging, or you may not have gotten one, but they are sold separately and are normally very cheap.


You've got what looks like a 1-1/4" tailpiece going into a 1-1/2 trap adaptor. With that type of pipe (white stuff) it may be difficult to find a fitting that allows you to reduce the size to 1-1/4. Your best bet is is to take the compression ring from the trap adapter and the tailpiece to the hardware store and replace the tailpiece with one that fits both your sink and the trap adapter.

This picture shows the components of a sink drain. enter image description herehttp://dogepay.me/sink-stopper-parts/sink-stopper-parts-sink-pop-up-stopper-bathroom-sink-drain-stopper-parts-small-images-of-parts-of-bathroom-sink-delta-bathroom-sink-stopper-replacement/

I would suggest changing all the white pipe but that may lead to more trouble. Adapting the tailpiece is your best bet. You may have to change the basin as well depending on how deep of a product line your hardware store carries.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.