Toilets, Sinks, Showers, Tubs and Disposals - Plumbing a new toilet - Is 3" Pipe Good Enough?

Doityourself.com community forum was created to provide answers to all questions related to home improvement and home repair. Doityourself community can help you find information about how-to topics on small fixes to large remodeling projects. With comprehensive how-to content and expertly moderated community forums DoItYourself.com makes it easy to tackle even the most complex home improvement projects.



PDA
plehry
03-30-08, 05:20 PM
I'm building a basement downstairs in my house and have plumbed in a new toilet, sink and bath. The main waste drain from the toilet is a 3" pipe, laid horizontally, that has one Y-connector. The main waste pipe for the house is a 4" cast iron.

The question is: is the 3" pipe OK for the toilet or should it be replaced with a 4" pipe?

j HOWARD
03-30-08, 06:23 PM
3" should be OK as long as it is sloped 1/8" per ft. to main
formula1
04-01-08, 02:12 PM
Check the code, if your waste drain is under concrete, I believe it is required to be 4" DWV pipe.

Terd Herder
04-03-08, 07:50 PM
Do four...whats the cost difference? $10?
thezster
04-03-08, 08:38 PM
FWIW - My last 3 basement bathroom additions had 3 inch pipe - under concrete - and all three passed code (2 different states).. Using a 4 inch pipe certainly wouldn't hurt - but since the toilet drain opening is only 2inches +/- - I figure that three inch pipe isn't gonna have issues...