View Full Version : Minimum tolet drainage

01-10-2005, 04:15 PM
I am installing a new bathroom on a concrete slab. Because I have enough ceiling height. I am going to raise the floor of the bathroom, to accommodate the drains.
Q-1 what is the size of the drain line for a tolet, and how much height should i have (above the 4" main line) for it to flow correctly.

01-10-2005, 06:07 PM
A toilet needs a minimum of a 3" drain line. All horizontal drain runs need 1/4" per foot.

01-10-2005, 09:08 PM
I hope that I do not offend you, but this is such a basic question that it gives rise to some concern over the tough parts of this job. Each and every fixture must be vented properly. There are very specific rules regarding the distance the vent can be away from its p-trap, the fittings you can use, and the way they are put together, especially when horizontally venting below the flood rim level of a fixture.
I also urge you to get this permitted and inspected. It can impact your ability to sell your home in the future, your homeowner's insurance coverage and other things.
The Pipewench