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Outdoor Drain To Sump (No P-Trap)

Posted: Sat Sep 15, 2018 1:47 pm
by tpirovol
Hi Everyone,

I have an outdoor catch basin that connects to my sump pit without a P-Trap. The house has an extension and the basement was lowered so they connected the drain to the sump as their are no sewers on that side of the basement.

I am sealing the sump for a radon mitigation and the installer found that the air intrusion from the drain without a P-Trap is to much for the system to work correctly. The pipe coming from the drain is a 4" and the sump pit cannot accommodate the 4" P-Trap.

My plan is to go from a 4" to a 3" via a 90' reducer and then 3"-2" reducer and then the p-trap. Just wondering if that would be an issue. The stairs and landing around about 6'x12' so their is not that much water. I also intend to ensure the p-trap is threaded so it can be cleaned.

I am just wondering if their is any other method of accomplishing a p-trap in a tight space? I was thinking of just running the 4" pipe down and into the water but would that also work?

looking for creative ideas
Thanks T

Re: Outdoor Drain To Sump (No P-Trap)

Posted: Sat Sep 15, 2018 11:23 pm
by Shannon
I think that the reducing would work but it will restrict flow in a heavy down pour. I think if you added a 45 and a short piece of 4" until the end was lower then the standing water level that would work as well?

Re: Outdoor Drain To Sump (No P-Trap)

Posted: Sun Sep 16, 2018 6:59 am
by tpirovol
K cool that is what I was thinking as well. I will try the trap reduced to a 3” and if that doesn’t fit I will do as you suggest.

Thanks as normal Shannon!