[RunningonMT]

Am having trouble in our 3 year old house with a plugged toilet! The problem is not consistent, but recently starting occurring after 5 or 6 "solid waste" uses.

(Ah yes, I can hear the jokes and feel the love already!)

I have a reasonable understanding of gravity flow in pipes, but am not super familiar with the applicable plumbing building code. After some research, it appears that the code requires a minimum slope between 1/8" and 1/4" per foot of run, depending on the diameter of the pipe. In the code, I don't see a maximum slope.

Online articles indicate the same minimum slope AND a maximum slope of 3" per foot of run. Vertical runs are also acceptable. The minimum slope provides enough gravity to keep the waste moving. Beyond the maximum slope, solids separate from the liquid causing pluggage. This might be my problem, since a 5 foot portion of the waste pipe is at a 45 degree angle.

BTW, I'm in North Carolina. If you know the correct code used in another state, please give me some references. I can follow up from there!

My questions:

Does the code have a maximum slope and I'm just missing it? If so, please help me find it!

What logic can I use to get the original plumber fix this issue?

Thanks for any help you can provide!