[lx255]

I am designing a septic system for a house on a steep hill. The septic system will be down on the flat area of the property and would like to place the septic tank there as well for ease of maintenance and installation.

The specifications along the pipe route from the two bedroom house to the septic tank includes a 66% (8" per foot) slope approximately 250 feet long. At the bottom, there will be a short run of 50 feet or so that will be closer to 5%.

I anticipate that we will be installing thermo-fused HDPE pipe via directional drill method.

I have read two different trains of thought regarding sewer on steep slopes and would like to get some "real-life experience" with those of you that may have had a similar situation. First point is relative to solids separating from liquids, and the second is vacuum/venting related issues. The project is in Michigan and I have reviewed the plumbing code and find no constraints that would not allow this to be done. Ten States Standards references only sewer main and at that only discuss restraints for pipes exceeding 20%.

Any thoughts?

 

[Bollinger plumber]

Go to intro thread and post an intro telling everyone how long you have been plumbing what code you use and what liciense you hold and you will get answers to your questions. this is a professional plumbers forum if you are not a professional plumber post your question in the diy forum. I am just saying.

 

[Miguel]

Dude, too bad you have "engineer" in your title as that's kind of a swear-word amongst us lowly types. Not slammin' you, man, in fact my niece is studying to be a civil engineer and my advice to her all along has been, "You GO, girl!". But we're all Plumbers here and we don't cotton to yer kind in these parts. (sniffs and does the ol' John Wayne swaggering stance)

But I like the question as I work in a really hilly (and rocky) terrain and have run into similar circumstances more times than I care to remember. All I can say is that the 30% full horiz and 60% full vert. rules really matter here! Deviate from that and you end up with the rooter guys on speed dial. Bit of a trick but in most cases can be done without using any 22-1/2 deg ells in the run.

Just my two bits. . .

 

[ILPlumber]

Are you a plumbing engineer?

If you are not, I must ask you not post here.

Thanks.

 

[waldrop]

gradeor slope

8' fall divided 250 run = 0.032 per foot fall x 100 =3.20% so it is not exceeding 20% where did you get engineer degree from auburn or clemson ?

 

[waldrop]

grades

66% for 250 feet of run would be 165 feet of fall:thumbup:

 

[Titan Plumbing]

We all know the liquid will not outrun the solids.

 

[SlickRick]

I have never unstopped a line and said "This line has too much fall on it".

 

[Pipe Rat]

OP stated 8" per foot of fall NOT 8' of total fall in 250' which is indeed 66% of fall.:yes:

 

[SlickRick]

Are you a plumbing engineer?.

No, but I did stay at a Holiday Inn Express.