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Sump Pump Battery Backup: Do You Need One, and What to Look For

Updated November 1, 2026 · General information, not plumbing or electrical advice

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Who this is for

Homeowners with a sump pump who want it to keep working in a blackout. The City of Ann Arbor says the factors to weigh are how often you lose power, how much you have invested in the basement, the age of the pump and check valve, and flooding history.

What you get

A second pump that starts on its own if the main pump loses power or fails. Ann Arbor says a battery backup runs on a deep-cycle battery for roughly 7 to 24 hours of pumping, is plugged into a household outlet so a charger keeps the battery full, and sounds an alarm if the power is out, the pump is running or the battery is low.

How to pick one

• Match the pump: Consumer Reports recommends a backup pump with a gallon-per-hour rate that matches or exceeds your primary pump's, accounting for vertical lift.
• Budget: Consumer Reports puts battery backup pumps at $100 to $300 or more, plus $100 to $400 for a battery.
• Battery: NDSU Extension says to use a deep-cycle lead-acid battery, and that the amp-hour rating sets the hours of protection. Check it every six months for charge and corrosion. Ann Arbor says batteries generally need replacing about every three years.
• Know the limit: Ann Arbor says failures can still occur in the pump or check valve, and that battery backups are usually less powerful than the primary pump.

The full comparison, including water-powered backups, is on our battery and water-powered backup page. Water-powered units are not an option on well water (Consumer Reports).

One thing that keeps it simple

Consumer Reports says battery backups are relatively easy for DIYers with basic plumbing knowledge. Check your local permit rules, unplug the pump before you handle it, and hire a licensed electrician or plumber for wiring and plumbing work.

A note on honesty

We have not tested any product, so we do not name a brand. The prices above are Consumer Reports' as of March 2025 and may have changed. If you buy through the link below we may earn a commission at no extra cost to you. It does not change what we recommend, including skipping a full backup if the checker says your risk is low.