I'm building a house and our proposed 4" sewer lateral runs a total of about 550ft. Starting elevation at the house foundation is about 89 ft. After about 100 ft it makes a 90 degree turn then goes for about 450ft. The existing 8 inch manhole is at 76 ft elevation. The County requires clean-outs every 100 ft. Do you have any suggestions or recommendations? With the 1/4" per foot rule, does it always have to slope down or does it apply to just the start and finish elevation over the run?
Sewer Lateral Questions/Recommendations
- Thread starter TLowing
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It must slope down continuously.
An 8 inch cleanout would not be called a manhole, I don't think. ;-)
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Bluebinky
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Not a pro, but here's my take...
The slope should be as uniform as practical, and always a minimum of 2%. You may be required to use 6 inch pipe for such a long run (my AHJ would require it, or possibly even 8 inch which would be a huge royal pain in Washington State with an easement, real manholes and such). One advantage of 6 inch is that you may be able to get away with 1% slope (1/8 inch per foot).
Legally getting into the 100 year floodplain and the creek buffer may be another can of worms.
The slope should be as uniform as practical, and always a minimum of 2%. You may be required to use 6 inch pipe for such a long run (my AHJ would require it, or possibly even 8 inch which would be a huge royal pain in Washington State with an easement, real manholes and such). One advantage of 6 inch is that you may be able to get away with 1% slope (1/8 inch per foot).
Legally getting into the 100 year floodplain and the creek buffer may be another can of worms.
