Install a battery backup sump pump beside the primary pump in the sump basin, wire it to a 12V battery and controller, then test it before use.
A storm outage is exactly when most sump pumps fail — the power that runs the pump is the power that’s out. You can install a battery backup sump pump in four jobs: mount the backup pump in the same basin, plumb a separate discharge with a check valve, wire the 12V battery and controller, and test the whole system before you rely on it.
What A Battery Backup Sump Pump Does
A battery backup sump pump is a second pump that runs from a 12V battery when the primary pump loses AC power, so the basin keeps draining through outages and primary-pump failures. The primary handles daily duty; the backup sits beside it in the sump basin and stays silent until it’s needed.
Most systems plug into a regular 120-volt outlet for the charger and controller, so no hardwired electrical work is required. Consumer Reports says a contractor can install a backup system in 2 to 4 hours, and typical retail prices for the unit run roughly $150 to $520, with installed cost around $600 to $1,200. Still comparing options? Our tested picks for the best battery backup sump pumps sort the models worth installing.
How To Install A Battery Backup Sump Pump In 7 Steps
Every major system follows the same order: kill power, wire the battery, mount the pump and plumbing, connect the controller, then test.
- Unplug the primary pump and shut off its power first. Verify the backup unit’s switch is OFF and the unit itself is unplugged before touching any wiring — that’s the shock-safety step every official manual leads with.
- Set up the battery in its protective box. Connect the controller’s red cable to the red terminal block and the black cable to the black terminal block, then fasten the black ring terminal to the battery’s negative post and the red ring terminal to the positive post. Tighten every connection, then close and secure the box.
- Find the Normal High Water level. Goulds Water Technology’s manual says to fill the sump until the primary pump turns on — that level sets where the backup tee can go.
- Mount the backup pump beside the primary in the basin, then place the discharge tee at least 2 inches above the Normal High Water level and at least 2 inches below the top of the sump. Keep the backup float clear of walls, pipes, wires, and the primary pump’s float, and check that the backup’s outlet and level switch don’t crowd the primary’s operation.
- Install a check
