Most people don’t think about their sump pump until they are trying to get four inches of water out of their basement during a rain storm. Here’s the scenario: a severe storm hits, you lose power to your house which means the electric sump pump is now worthless and the basement floods. The solution? A battery powered sump pump. Right? Maybe not.
For houses on city water, battery powered backup sump pumps will probably go the way of 8-tracks and VCR’s because there is a newer technology on the market: water powered backup sump pumps. It sounds counter-intuitive to use water to get rid of water, but it’s elegant and simple. City water is used to run a small pump which pumps the water out of the sump pit. For every gallon of city water used to run the pump it pumps out two gallons from the pit. The obvious advantage is that in a storm, when you are likely to lose electricity (and when you need your sump pump the most), you don’t lose city water. Check out this YouTube to see an example of how a water powered pump is installed:
http://www.thisoldhouse.com/toh/video/0,,20260244,00.html. The price is competitive with a battery backup especially when you factor in the price of a high quality battery. More importantly the peace of mind can be worth it.
If your house is served by a well then this is not an option for you since your well pump is non-functional during a power loss. A battery backup sump pump can provide a short window of protection (typically 6-8 hours of runtime) but it may not be sufficient for a longer power outage. In that case, it would be worth thinking about a backup generator power supply for all of the critical electrical components in the house including the sump pump.