reccomended sanitary drain grade (rise/run)

[murena]

I am installing two drains into a 3" stack that is outside my house. The first is a shower drain with 2" ABS, the second drain is the tub with 1.5" ABS. The tub drain is about 6 feet from the stack, while the shower is about 10 ft. My question, what is the reccomended grade for these types of drains? I have heard that 1/4" rise per foot run... but that seems pretty steep, and will mean I will lose more ceiling height. Please help, want to get the drains completed soon. Mike

[Gary Swart]

Minimum slope for all drains is 1/4" per foot. Even if you slipped a lessor grade past an inspector, you would be plagued with clogging problems forever. This is one of the problems a DIYer can run into after getting deep into a project. Sorry, but you can't ignore this one.

[murena]

Just wanted to make sure the numbers were right..

Thanks

[hj]

Now that you have the slope correct, what are you doing to provide vents for those drains? Installing a tub and shower involves more than just running a drain pipe from them and connecting it to the first available drain line.