So, we live in an area that is pretty wet. Sump pump runs all the time and frequently. Interestingly, heavy rain does not seem to change the amount of flow. It is pretty steady.

What I noticed when checking my battery operated back up pump was the pit would eventually stop filling up. It would get to about half way up the intake pipe and just stop (to be clear I mean there is about 2 inches of water in the intake pipe when I stops). I noticed this as I unplugged my pumps to simulate a pump failure, but the water never got high enough to trigger the back up.

What I am wondering is whether I should raise the float switch up to have it just a fraction above the point where the water seems to stop flowing in. Why pump water out to just create space for new water.

Is there any downside of have water sitting in the pit and in the pipes that lead to the pit? The pipes would never be more than half filled in terms of level…that is, there would always be about two inches of head space above the water in the intake pipe. I would set the pumps to engage at that level. In some ways all I am doing is creating a bigger pit.

  • If you promise to drain all water out about once a week, to change it for fresher water, it should be okay. Sitting/stagnant water can lead to health problems, if left for periods of time.
    – crip659
    Jul 27, 2021 at 22:41

1 Answer 1


I set mine so the backup pump normally does not run. When the water gets about an inch above the normal pump turn on point the backup will then come on. You need to be sure the backup turns off before the primary pump otherwise it will be running at the wrong times. The water rises seaking its level point. That water is in the footer tiles of your home. The tiles have a lot more room to store water then your sump, given enough time it will continue to slowly rise. If the water stops rising and you let it sit for a while it will take a noticeable longer time to shut down. I check mine every week and I also have an alarm so if the backup comes on the alarm sounds. You can power it with the lines and if the power is out it will not squawk.

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