Ok I’m in a rental 2200 ft house that sits 400 ft off the road
There is a sewage pit in the basement that has two pumps in it , steel cover about 3ft diameter
The 4” pvc drain goes into the concrete floor next to the pit
There are two 2” pvc pipes coming up straight out of the cover , each has a check valve.
They come up vertical about 3 ft then 90 and go horizontal about 2ft and y together .
Then 90 back vertical into the floor
I see a 4” pvc going out the wall .
Not sure how everything ties together under the floor but here’s my question
A few times during the day I hear the pumps come on and run a minute even when no water is running in the house.
I’ve checked all three toilets etc , nothing is leaking .
Only thing I can think is the tank is leaking ground water in a little ???
Does this make sense ?
I put my ear against the pipes above and below the check valves and hear nothing
Any ideas ?

3 possibilities.

one or both check valves is leaking by ?

ground water entering thru a defect in the tank or piping ?

ground water entering by design to keep the basement from flooding ?

of course something in the house could be running but you said you've checked that.

BTW, there should be three pipes coming out of the cover. 2 are discharges and the third should be a vent



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