help -- simple plumbing question

[gobug]

My books are packed away and I am doing some plumbing repair.

What is the proper amount of drop in a drain line over 10 feet - or 8 feet?

thanks
GO

[Obser]

I use one eighth to one quarter inch per foot. Never had a problem. Don't know what the books say.

[Abuelo in TX]

The plumbing code used to specify 1/4" slope per foot. I doubt it has changed

[raymilosh]

code here requires 1/4 inch per foot, but people say you can get away with as little as 1/8 inch per foot if you really really need to. I have heard that "half a bubble off level" is about right. I think i remember trying that on my pipes after i carefully calculated and laid them and that it worked. Please verify it for yourself before you just take my advice though

[kmaproperties]

1/4 per foot max. if you go too steap the solids will stick to the walls and the liquids keep going. you then build up a plug.