I have been told that 3-inch drain from a toilet acheives a better "swirling" action than larger 4-inch pipe, therefore helping to carry away solid wastes better. Is this true ? and if so, how far should I run before opening up to the main 4-inch waste line that exists my concrete slab ?

speedball1

"I have been told that 3-inch drain from a toilet acheives a better "swirling" action than larger 4-inch pipe"

Whoever told you that? Using that logic reducing to 2" or 1 1/2" oughta give you one hellava flush.

Code will allow you to rough in a toilet on the 1st. or 2nd. floor at 3 inches.
However on a slab or basement under the cement you have to rough a toilet in at 4". good luck, Tom

JMars

Thanks Tom, Something tells me I will be using this forum again. I think a lot of the self-help "Harry-Homeowner" books leave out details that make the difference between a job done right vs. a job....... well you get the idea!