reccomended sanitary drain grade (rise/run)

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

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.

Ok, good to know...

Just wanted to make sure the numbers were right..

Thanks

drains

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.