Guides ยท Updated 2026-11-13
How do I flush my water heater?
Quick answer: Turn off the power or set the gas to pilot, shut the cold water supply, drain a few gallons through a hose at the drain valve until the water runs clear, then refill the tank completely before turning the power or gas back on.
Step by step
- Turn off the power at the breaker for an electric heater, or set a gas heater to Pilot.
- Let the water cool for a few hours. Tank water is hot enough to burn.
- Close the cold water supply valve on top of the tank.
- Attach a garden hose to the drain valve at the bottom and run it outside or to a floor drain.
- Open a hot water faucet in the house, then open the drain valve.
- Drain until the water runs clear. Open the cold supply briefly to stir and flush the sediment.
- Close the drain valve, remove the hose, open the cold supply, and let the tank fill until the hot faucet runs steady with no air.
- Only then turn the power back on or set the gas back to On.
The Home Maintenance Minute
Never turn an electric water heater back on before the tank is full. Heating an empty tank can burn out the element.
Never turn an electric water heater back on before the tank is full. Heating an empty tank can burn out the element.
When to call a pro
Call a licensed plumber if the drain valve won't open or leaks, or if your tank is over 10 years old and you see rust or water at the base.
By The Home Keeper Team. General information only, not a substitute for a licensed pro.