Running PVC drain under ground

Old 09-30-17, 09:59 AM
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Running PVC drain under ground

I have a sump pump that I set up running the drain through the basement to the outside. It runs maybe once a week only draining some water from the water softener.

I want to bury the outside part of the drain and run the pvc pipe out into the woods maybe 50 feet from the house, going down hill.

1. Does it matter which PVC pipe I use.
2. Even though the pipe will never be filled with water for more than a few minutes, should I bury it below the frost line?

Any help is greatly appreciated.
Old 09-30-17, 10:12 AM
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You don't say where you live so I want to be careful on my answer. If you can be certain water will remain in the pipe for only a few minutes, you shouldn't have an issue with flowing water freezing in the pipe. However, I suspect you may not be as certain as you think.

What is the water flowing into? Unless the water freefalls at the end of the pipe (perhaps into a culvert), you run the risk of congestion at that point as the water is being absorbed. Beyond that, if the water starts slowly or ends with slow running water, you run the risk of freezing.

In addition to the risk of freezing, you also risk pipe movement from heaving to consider.
Old 09-30-17, 06:20 PM
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The best way to accomplish what you want is to run a larger pipe from the house underground to the woods. Say a 3" or 4" pipe. Then have the sump pump pipe drain into it -but leave an air gap. Don't actually connect the two pipes. Stick one into the other (like your washing machine drain.

This will allow the water to flow out the pipe and not keep the pipe full of water. Also, if the pipe does freeze, it will allow the water to overflow the pipe, and not force the pump to try pumping into a frozen pipe.
Old 10-02-17, 05:48 AM
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In addition to the good advice you've gotten, I'll add that PVC pipe comes in several wall thicknesses and the thin stuff collapses very easily underground. I'd use at least SDR 35 (slip together joints with rubber seals) or sch 40 (glue joints). Good luck, Steve

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