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 sewer drain line fall per foot
Author: abolick1947 (NC)

How much drop per foot should you have on you main sewer line running to the street? Can you have too much fall?

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 Re: sewer drain line fall per foot
Author: jimmy-o (CA)

Generally, minimum is 1/4" per foot. A four inch or larger can sometimes fall at only 1/8" per foot.

Although the topic is widely debated, there is probably NO maximum fall rate. As far as my reading has ever uncovered, it is strictly a MYTH that if the pitch is too great, the water will outrun the solids.

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 Re: sewer drain line fall per foot
Author: North Carolina Plumber (NC)

Since you are in NC, you'll have to run 4" to the street. 1 inch in 8' is the minimum, there is no maximum.

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 Re: sewer drain line fall per foot
Author: calsplumbing (CA)

1/4" per foot is what the UPC calls for. But you could get a variance of 1/8" per foot with your local code approval.

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 Re: sewer drain line fall per foot
Author: hj (AZ)

Here, you would have to have an engineer's stamped drawing before they would approve anything less than the code approved minimum. I once did a 300' sewer at 1/16" because that was all that was available between the building invert and the city's main.

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