herlihyboy wrote:
I have a basement sump for my basement bathroom. It pumps up about 4'
to the main drain that goes out to my septic. We just bought the house
and I need to put a backflow check valve in it. How far between the
sump and the elbow that goes out should I put the valve? Does it
really matter? Didn't know if it should be down closer to the sump, up
where it goes out, in the middle, etc.?

Thx!


Put it close to the pump, that will prevent the water in the
vertical pipe from falling back into the sump.

There is another issue: That ground water shouldn't be
discharging into the sanitary (septic) line.
It may have been "convenient" when the previous owner
had it done, but it should have a separate drain line
to ???

Jim