Our house is has a drilled well, with with 1/2 HP 230V well pump wired from a fixed pressure switch. We've had a couple of pinhole leaks in the copper piping that would have turned into major basement floods had we not happened to be home at the time. I would like to reduce the impact of any future leaks by using a float switch in the basement sump pit to cut power to the well pump in case the sump pit begins to fill. My understanding is that, once the float switch triggered, this would limit the amount of water that could flood to the amount in the pressurized well storage tank (about 10-15 gallons).

The plan is:

  • Wire the float switch (http://www.dwyer-inst.com/Product/Level/LevelSwitches/Float/SeriesCFS2) in series before the pressure switch. The float switch is rated 240V and 10(8)A which as I understand it is enough for the well pump -- it seems that 1/2HP 230V draws a maximum of 6A.

  • Use a clamp to fix the float switch cable to the side of the sump pit (which is already lined with wood so that it floats at a few inches in the sump pit.

Does this make sense? Is there something I am overlooking?

  • 1
    This may sound like a good idea but consider a wet year where the sump fills from a high water table, now you have no water, I guess it could have you checking your basement if there is no water.
    – Ed Beal
    Apr 27, 2017 at 13:25
  • Is there a chance that the copper piping was from a bad batch and it would be better to get it replaced? Apr 27, 2017 at 18:16

1 Answer 1


My recommendation is to build a "float pan" under the run of Cu pipe in question. As Ed Beal suggested, don't depend on the sump pump as a diagnostic tool. The pan only needs to be an inch or so deep, as you expect it to be bone-dry all the time. Put a float valve on the pan, and tie into well pump power as planned.

BTW, I didn't come up with this on my own: central air conditioners' air exchange handlers have this sort of arrangement, to avoid disaster if the drain line clogs.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.