View Full Version : Differences between toilet, shower, and sink drains

jen mc
Dec 27, 2009, 11:57 AM
I have two very small bathrooms that I want to combine into one. I would like to rearrange the location of the fixtures without moving the plumbing.

Can I put a shower drain where the toilet used to be? Can I put a sink where the shower used to be? What is the difference between a shower drain fitting and a toilet drain fitting?

Also our home was built in the 1960's and the shower and tub drains are not set in concrete. We found dirt under our fiberglass tub and shower.

Milo Dolezal
Dec 27, 2009, 04:14 PM
Hello Jen MC, you will have to modify your existing drains to accommodate your new bathroom lay-out.

Toilet uses 3" or 4" drain w/o trap.
Shower uses 2" trapped drain
Sink uses 1 1/2" or 2" drain w/o trap.

To connect shower to the toilet drain, you will have to cut off existing Closet 90 bend fitting, reduce it to 2", and install 2" trap.

Sink drain is on the wall, not in the floor. You will have to cap off existing shower drain. Then, open wall, cut into shower vent, install 2" x 1 1/2" San "T" about 15" above the floor and lead this horizontal pipe to the sink location mantaining 1/4" per foot slope. This horizontal pipe should not be further than 42" from the Sanitary "T".

If you post sketch of your old and new lay-out, we could help you to design your drains.

Good luck... Milo