After living in a house for a year, I noticed my backup sump pump discharge pipe is 1 1/2", but then changes to 2" before it goes outside. It changes to 2" about 2/3 up the vertical section. The pump runs OK when tested but I'm worried in case of a real emergency that it'll burn out quick.

Am I being paranoid? Has anyone seen a battery backup pump with a 2" discharge?

1 Answer 1


I fail to see a problem here. Increasing the discharge pipe diameter does not increase the load on the pump. Unless you have a pump manual that specifically forbids this (which seems very unlikely) relax and stop worrying about it - or worry about the battery running out, which is far more likely to be a problem in any extended power outage.

If you have such an unlikely manual, replace the pipe that offends you/it.

  • Indeed. If anything the larger pipe diameter reduces the load on the pump by reducing the frictional losses in the pipe, and therefore reducing the backpressure.
    – mac
    Mar 14, 2014 at 20:21

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.