I'm researching backup sump pumps for my existing sump (a 3.5 year old Zoeller that's been working great). I'm considering the city water pressure system as opposed to the common battery backup, and am curious about your experiences. Please assuage my fears that adding more water to the situation will not do my home harm.

I live in an old, renovated rowhouse. I know that if my sump pump is not running, I will get at least a little bit of water in my finished basement if there's heavy rain and my sump pump is not working (and if I catch it quickly).

Plumber has checked my water pressure, and says it's fine.

Do you have one of these systems? Have you seen it in action - like actually come on during a power outage? How did it do? Did it do serious damage to your water bill? Is there anything I should be aware of or on the lookout for?

  • 1
    In the event that you need it, you hold the water bill in one hand, and what you didn't spend on flood remediation in the other... Third path is to renovate the finished basement to be "flood friendly" with ceramic tiles up above however high "a little bit" is so that water entry does not equal damage, just some cleanup.
    – Ecnerwal
    Jul 18, 2023 at 14:24
  • 1
    For a somewhat larger investment you can add stages such as battery-backed or having a generator before you hit the float level for the water-based pump. Unless your municipal water costs a lot, the water bill once in a while might be less overall cost, though.
    – Ecnerwal
    Jul 18, 2023 at 14:35
  • How much water does your sump pump during a storm? For me, it's probably about 5gal every 5 mins, or 1g/m. Considering the water-powered ones go at least 2:1, you're talking 30g/hr for a few hours a few times a year; surely that not very significant water cost-wise, a few extra showers a year.
    – dandavis
    Jul 18, 2023 at 17:54

1 Answer 1


I don't have one yet (emphasis on "yet"), but they're venturi pumps, similar the the ones you can screw into the middle of a garden hose, and I have seen one of those used to empty a 40'x80' swimming pool over the course of about a week so I can attest that the principle works. It consumes a considerable amount of fresh water in the process, but it works as long as sufficient water pressure is available, and towns usually have lits of backups for that.

The main difference between the sump-pump version and the inline hose version is that the former has a float controlling an inlet valve, so it runs (and stops( automatically based on water level. Also, it's usually designed for more permanent installation.

Inexpensive insurance if you think the same storm causing the flooding might knock out your electric power for longer than your main pump's battery backup (if any) will hold out.

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.