Best battery backup
Zoeller Aquanot Spin 508 12 V Battery Backup Sump Pump System
Self-testing 12 V backup rated on a real battery
Backup sump pumps
A backup sump pump takes over when the power goes out or the main pump fails, for basements that can’t be left to flood.
Used for: Flooded basement and sewer backup
Our picks
Best without a battery
Basepump HB1000-PRO Water-Powered Backup Sump Pump
No battery: runs on city water pressure for as long as it lasts
Best backup display
Liberty Pumps 442-10A StormCell 12 V Battery Backup Sump Pump
Pro-grade 12 V backup with LCD panel and redundant float
Compare side by side
| Specification | Best battery backup Zoeller Aquanot Spin 508 12 V Battery Backup Sump Pump System | Best backup display Liberty Pumps 442-10A StormCell 12 V Battery Backup Sump Pump | Best combo system Basement Watchdog Combo CITE-33 Primary and Battery Backup Sump Pump System | Best without a battery Basepump HB1000-PRO Water-Powered Backup Sump Pump |
|---|---|---|---|---|
| Price | ||||
| Our score | Our score: 8.2/10 out of 10(best in this row) | Our score: 8.0/10 out of 10 | Our score: 7.6/10 out of 10 | Our score: 7.9/10 out of 10 |
| Backup flow at 10 ft | 1,800 gal/h | 1,800 gal/h | 1,000 gal/h | 1,000 gal/h |
| Works in an outage | Yes | Yes | Yes | Yes |
| Continuous run on battery | 5.5 h | 5.5 h | not listed | not listed |
| Water pressure needed | not listed | not listed | not listed | 40 psi |
| Switch | Vertical float | Pipe-mounted float switch | Dual float switch | Float-operated water valve |
| Minimum pit width | 16 in | not listed | 10 in | 10 in |
| Phone alerts | No | No | No | No |
| Warranty | 3 years | 3 years | 2 years | 5 years(best in this row) |
| Where to buy |
US retailers |
US retailers |
US retailers |
US retailers |
Before you buy
- Check backup flow Compare backup flow at 10 ft and how many hours one battery runs. Backups pump less than primaries.
- Water-powered needs city water It also needs a backflow preventer, and some towns limit it. Our battery vs water-powered guide compares the two.
- Get an alarm that works offline Choose a backup with a loud alarm that sounds without Wi-Fi, so you know it is running.
Need a backwater valve, sump pump or drain fixed?
Pick the job, then your city.
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Guides
Best-of
The best battery backup sump pumps
Four backup sump pumps compared on the makers' own figures: flow at 10 ft, run time per battery, pit size and alarms that work offline.
Comparison
Battery vs water-powered backup sump pumps
Battery backups pump harder and work in any home; water-powered ones run through long outages but need city pressure, a backflow preventer and your town's approval.
How-to
Basement flooded? What to do first
Power and safety first, then sewage or clean water, photos for your insurer, slow pumping and drying within 48 hours, in the order official guidance gives.
Backup sump pump questions
Does a water-powered backup pump need a backflow preventer?
Yes. It runs on mains water pressure, so the drinking water must be protected; some towns require a reduced pressure zone (RPZ) valve tested by a licensed plumber. Some cities ban water-powered backup pumps outright, so ask your municipality and a plumber before you buy.
How much water does a water-powered backup use?
About 2 gallons of mains water for each gallon pumped out of the pit, billed as normal use, by one city’s figures. It only runs when the primary pump has failed, but in a long storm that adds up.
How often should I test a backup pump?
Test a water-powered backup about twice a year with the primary pump unplugged. For battery systems, follow the maker’s test and battery schedule, and pour water into the pit to check the backup switch starts the pump.