In this video, damage-prevention specialist Michael Milligan shows how to avoid a soggy disaster.
How to Keep Your Basement from Flooding
- Standard sump pumps do a good job of removing water from a flooded basement, but they don’t operate during a power outage.
- Sump pumps equipped with a battery-backup system will continue to run even if the electricity goes out. The rechargeable battery will operate for about seven to 10 hours before recharging is necessary.
- Water-powered sump pumps rely on water pressure, not a rechargeable battery, to keep pumping during a blackout.
- A water-powered sump pump will run virtually forever, as long as there’s water pressure. Note that this system is only suitable for homes connected to a municipal water supply, not a well pump.
- Label the water-main shutoff valve, and then be sure that everyone in the family knows how to find and close the valve in case of an emergency.
- A water-leak detector is useful in detecting and then alerting you that there’s a leak.
- A whole-house leak detector uses wireless transmitters that can be placed throughout the house to detect and then automatically shut off the water in event of a leak.
- A programmable auto-shutoff leak detector is designed to detect a constant flow of water, at which point it turns off the water.
Beyond battery backups, there’s another option: a water-pressure-powered backup sump pump. As demonstrated on This Old House, this type connects to your home’s city water supply. When the primary pump fails and the water level rises, a float switch opens a valve that sends pressurized city water through the unit. As the water rushes through and makes a 180-degree turn toward the discharge pipe, it creates suction that draws floodwater out of the sump pit — no electricity or battery required.
Pro Tip: Richard Trethewey, This Old House plumbing and heating expert, explains why a backup is essential: “Usually when the basement floods, you have heavy rain. When you have heavy rain, you can lose power.” That’s precisely when your primary electric sump pump becomes useless — and when you need protection the most.
Pro Tip: Richard Trethewey, This Old House plumbing and heating expert, stresses the importance of a backup system: “If you’ve got a finished basement with nice carpets and wood moldings that’s below the water table, a backup is cheap insurance.”
Why It Matters: According to This Old House plumbing and heating expert Richard Trethewey, “There’s nothing more horrifying than coming home and seeing water coming out of the walls.” He notes that a main shutoff valve will either turn clockwise to close or may be a ball valve with a lever handle. “Once you do that, full stop, the house is no longer pressurized. The leak should stop.” From there, you can assess the damage and call a plumber in the morning.
Pro Tip: Richard Trethewey, This Old House plumbing and heating expert, stresses that labeling is essential: “We recommend to people that they put some sort of a tag on that so that if there is a problem, everyone knows where to go to go ahead and pull that valve.”
