Best Battery Backup Sump Pump (2026): 5 Picks to Keep Your Basement Dry

• Type12-volt battery backup system, added to your existing pump
• FlowUp to 2,500 GPH; 1,680 GPH at 10 feet of lift, per Wayne
• Run timeUp to 26 hours at 5 gallons per minute with a 75 Ah battery, per Wayne
• AlarmsAudible alarm when the backup runs; LED battery status light
• Battery12V battery sold separately (Wayne recommends its 75 Ah WSB1275)

The Wayne ESP25 is a well-regarded battery backup that installs alongside your existing pump. When the main pump fails or the power goes out, it switches on by itself and sounds an alarm. Its smart charger keeps the battery topped up, and a light shows the charge status.

Wayne rates it for up to 2,500 gallons per hour, and up to 26 hours of protection with its 75 Ah battery at a steady 5 gallons per minute. The battery is sold separately, and like all battery backups, it cannot run forever in a very long outage. It has a 2-year limited warranty.

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• Type12-volt battery backup system
• Flow3,500 GPH; 2,200 GPH at 10 feet of lift
• Run timeAbout 40 hours at a 10% duty cycle with one BW-27AGM battery; add a second battery to double it
• AlarmsController with alarm and problem lights; weekly self-test; Wi-Fi module sold separately
• Charger20-amp smart charger; dual float switch

Basement Watchdog is one of the best-known backup brands, and the Big Dog CONNECT is its most powerful battery backup. It moves 3,500 gallons per hour, and its dual float switch gives a second way to start the pump if one float sticks.

The controller tests the pump every week and warns you about problems like a low battery. Add the Wi-Fi module, sold separately, to get text, email or app alerts. You can connect two batteries for longer run time. The battery is sold separately, and the large box takes up space near the pit.

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• Type12-volt battery backup system
• Flow2,600 GPH; 1,850 GPH at 10 feet of lift
• Run timeAbout 48 hours at a 10% duty cycle with one BW-27AGM battery
• AlarmsController with alarm and lights; weekly pump exercise; Wi-Fi module sold separately
• Warranty2-year limited (up to 4 years with an AGM battery and online registration)

The Special CONNECT is Basement Watchdog’s smaller, lower-cost battery backup. It moves 2,600 gallons per hour, or 1,850 at 10 feet of lift.

Like the Big Dog, it has a dual float switch and a controller that watches the pump, power and battery. It runs the pump each week to keep it in shape.

Add the BW-WiFi2 module, sold separately, for text, email or app alerts. Basement Watchdog rates it at about 48 hours at a 10% duty cycle with one BW-27AGM battery, which is sold separately.

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• Type1/2 HP primary pump plus 12V backup, pre-assembled
• Primary flowUp to 5,100 GPH; 3,840 GPH at 10 feet
• Backup flowUp to 2,900 GPH; 1,680 GPH at 10 feet
• IncludedTwo check valves, pre-plumbed; battery sold separately
• BasinFor sump basins 15 inches wide or larger
• Warranty5-year limited

If your main sump pump is old, a combination system replaces it with a new 1/2 HP primary pump and a battery backup that come pre-assembled, with two check valves already in place. That makes installation much simpler.

The primary moves up to 5,100 gallons per hour, and the ESP25-based backup takes over in an outage. It costs more than adding a backup alone, and the battery is sold separately. If your current pump works fine, a standalone backup makes more sense.

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• TypeWater-powered (uses city water pressure)
• FlowAbout 900 to 1,400 GPH (published), depending on water pressure
• NeedsCity water at 40 to 90 psi and 3/4-inch supply pipe
• Alarm85 dB high-water alarm included (9V battery)
• IncludedBackflow preventer, ball valve and push-fit fittings; 5-year warranty

Water-powered backups use your city water pressure to pull water out of the pit, so they keep working for as long as the outage lasts, with no battery to replace. Basepump says one gallon of city water removes about 1.5 to 2 gallons of sump water.

The HB1000-PRO comes with a backflow preventer, a shutoff valve and push-fit fittings, plus an 85 dB high-water alarm. It only works with city water at 40 to 90 psi, it uses water when it runs, and local codes may require a specific backflow device.

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