My sump pump does a great job of keeping my basement dry even in heavy rain. But I worry about what will happen if I lose power during a heavy storm (like a hurricane) and my sump pump is unavailable.

I spoke to my plumber about sump pump backups, and they recommended digging a second sump pit with a dedicated backup pump that would be powered by either a marine battery or by the water pressure in my home's water service.

Both of these options were fairly expensive, so I was wondering if there are other options. I could get a gas generator and run extension cords into my basement, but is there a simpler option?

For example, is there a battery that has a conventional 110V electrical outlet and could power just the sump pump for a period of 1 - 3 days?

  • What lame excuse did they give you for not being able to use the same sump...
    – Mazura
    Aug 3, 2016 at 17:00

4 Answers 4


In most cases an extra sump pit is pure plumber profit - if the sump is not tiny, the backup pump can use the same sump, and just be set to come on at a higher water level.

The practical problem with your vision of "a battery with a 110V outlet" (battery charger, battery, and inverter) is that is entirely possible, but wickedly expensive; also, batteries don't last forever, both in the "length of power outage" and the "number of years before you have to scrap them because they no longer work at all" sense, so it gets even more expensive. Sump pumps with a battery backup built in are made - they have many of the same problems, but usually skip the added inefficiency of converting back to 120 VAC and just use a DC pump.

If you have utility water, and such things are acceptable to your utility, the water-powered sump pump has the benefit of being fairly inexpensive to own, being based on a power source you don't have to buy and maintain. You will get a big water bill if you need to use it. If you have a well pump, it's useless.

Anything depending on you running a generator depends on you being home, the generator being functional, and adequate fuel for the generator being available in the event of a prolonged outage - which it often is not, since the filling station does not have power either. You can expensively address most of those with an auto-start natural gas powered unit if you have natural gas available...

You can also use only tile or concrete for surfaces in your basement and not put things that would be bothered by getting wet in it, so that the occasional flood is less traumatic. How badly or quickly it floods if you turn the sump pump off might guide your thinking on this. It can be very expensive to build and maintain a pumping system that will work though a long, widespread power outage.

  • 1
    I don't know that "wickedly expensive" is necessarily true. Battery backups kits, with battery included can be had for under $200, and many basically are a float charger, a deep cycle battery, a high water switch and a DC pump. Had one installed for many years without issue. A quick google search turns up a big box kit for $147, pump included. Aug 3, 2016 at 12:27
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    Does it run the sump pump for 3 days? By the time it does, it will be wickedly expensive, unless the sump pump barely runs.
    – Ecnerwal
    Aug 3, 2016 at 13:31
  • I think there are too many variable to answer that. It has definitely had to run more than 24 hours at a time. What it really comes down to is, how high is the water table, what's the current approximate duty cycle and capacity of the current pump. Knowing these things, you could begin to back in to what kind of backup pump is needed. Most people don't expect 100% capacity of their primary pump, unless it's a finished basement. Aug 3, 2016 at 14:09

I was recommended a sump jet for the same concerns. I haven't gotten one yet but from what I gathered, it is a water powered back-up sump pump that will protect your basement in the case of a power outage. It is powered by water.


We live in an area where there's a relatively high water table, so our sump pump runs on a regular basis. Typically not a huge quantity of water (unless there's been a bunch of recent rains), but the pump will occasionally run for about 9 months of the year. Since our basement is mostly finished, I thought it to be critical to not only have a battery backup, but also a second functioning pump in case the primary one failed. My sump pit was plenty big, so my pit has two pumps in parallel. One is the standard 110v pump with float switch, and the second is a completely independent 12V pump with its own float switch. The 12V backup pump is run from a deep cycle marine battery with its own trickle charger and it all came as a set, except for the battery. I think the brand is Zoeller, but can't recall for sure.

The backup doesn't have nearly the pumping capacity of the main pump, but it will still drain the sump plenty fast for our needs. Just need to make sure the battery is replaced every few years even if it hasn't been used.

One thing I needed to do was put check valves after each pump (and before the two pump lines joined to go out of the house), or else one would just pump into the other and not remove much of any water. Don't skimp on the quality of the check valve, as I had one fail shortly after installation, and so I was just pumping out of my main pump and backwards through my backup pump.

Also, one other thing I have done is to have a spare 110V sump pump already purchased, along with all needed PVC pipe, attachments, and Fernco couplings to make quick work of changing out my main sump pump when (and not if) it eventually fails. History has proven (thankfully not directly to me) that sump pumps will often fail at the worst times (middle of the night, or after very heavy rains and the stores are sold out of replacement pumps), and it's nice to know that I have a replacement pump ready to go, just in case.

Finally, home insurance policies often don't cover sump pump failures, so check your insurance policy. In our case, it was quite inexpensive to add a separate sewer/water backup rider to our policy which covers sewage backups, water backups, etc.

The importance of having a good sump pump system and backups should be inversely proportional to the amount of damage you're willing to accept and pay for if something fails in your current pump system. If you don't care about potential damage, the importance is low. If you have valuable things in your basement that could be damaged, then the importance of having backups and insurance coverage is high.

  • Yes, Andy, you are correct. I've modified my original reply.
    – Milwrdfan
    Aug 4, 2016 at 14:00

If you're on municipal water, it's hard to beat a water powered backup pump. A typical unit will remove about 2 gallons of sump water, for each gallon of municipal water used.

If your water supply is from a well, a battery backup is a good option. Just make sure the battery is always charged, and in good working order. Battery backup systems can be had for as little as $150-$200, though you'll also have to consider the additional cost of replacing batteries as they age.

In either case, the cost of water used or replacement batteries, is likely far less than the cost to repair water damage caused by a flood.

You should be able to install a back up in the same pit, you'll just set the float switch a bit higher than the main pumps switch.

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