Plumbing in the Home/sewage pipe


I have a septic tank. I need to replace the pipe from the cleanout. It is only about 20 feet long. I have all the parts.
I bought pvc pipe, however, it is not schedule 40. The guy at Lowes said the thinner pipe would be fine for my needs. A friend came over and told me since it is not that far below ground, that I need a sturdier pipe schedule, i.e. sched. 40.
Is that true? The pipe we are replacing in very thin, but it did end up with holes from tree roots.

Hi Janet,
Frost line is not an issue for you most likely but the "standard depth" for burial is 18 inches minimum.  Obviously, this depends on the depth of the inlet to the septic tank. You need to maintain the proper 1/4 inch/foot of slope. That would be 5 inches drop over a 20 foot run.

While thinner wall pipe might work just fine, the consequences of a sewage spill from a broken line can be quite expensive to clean up. Your call.
Good Luck,

Plumbing in the Home

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Dana Bostick


Pretty much any residential plumbing questions. For "item specific" details such as a specific model of fixture, I will need to research and there may not be any useful information available. Note: I live and work in Southern California. We do not, as a rule, use hot water or steam heating systems, oil fired boilers or private water wells so my knowledge in those areas is pretty limited. There are others here on AllExerts that can probably answer those questions better.


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