How to Flush and Drain Your Water Heater

Flushing your water heater is one of those maintenance tasks that prevents expensive failures down the road. Sediment builds up at the bottom of the tank—minerals from your water supply settle out and harden—and that buildup reduces efficiency, creates noise during heating, and shortens the heater's lifespan. You're not rebuilding anything here. You're just opening a valve, letting gravity do the work, and giving your heater a chance to run clean again. The whole job takes about an hour and costs nothing but water. Gas or electric, the process is identical. You'll know you're done right when the water running out of the drain stops being cloudy and turns clear. After that, you're back to normal operation.

1. Kill the Power First. For a gas heater, turn the thermostat dial to the pilot position. For an electric heater, switch off the dedicated circuit breaker. Wait 30 minutes to let the water cool slightly—you're not trying to drain boiling water.
2. Stop Water Supply Now. Locate the cold water shut-off valve on top of the heater (usually a lever handle or ball valve). Turn it clockwise or flip the lever to the perpendicular position. This stops fresh water from entering while you drain.
3. Route the Water Out. The drain valve is at the bottom of the tank. Screw a standard garden hose onto the threaded outlet. Point the other end into a floor drain, a bucket, or outside through a basement window. Hand-tighten only—you're not sealing a gas line.
4. Release the Sediment Flood. Turn the valve handle counterclockwise or pull the lever toward you. Start slow—let a little water out first to confirm the hose is directing flow where you want it. Once you're sure, open it fully. You'll see discolored, cloudy water initially.
5. Repeat Until Water Clears. Once the sediment-heavy water stops flowing, open the cold water inlet valve again for 30 seconds, then close it. This sends fresh water into the tank and stirs up any remaining sediment. Open the drain valve again and let another gallon or two flow out. Repeat this flush-and-drain cycle 2-3 times until the drained water runs clear.
6. Seal and Disconnect. Turn the drain valve handle clockwise or push the lever away from you until it stops. Wait a few seconds for drips to cease, then unscrew the garden hose. You may feel a small amount of water trapped in the hose—that's normal.
7. Bleed the Air Out. Turn the cold water inlet valve back on fully. Open a hot water faucet on the nearest fixture (usually a sink or shower) and let it run for 30-60 seconds. You'll hear air sputtering out; wait until a solid stream of water flows. Close that faucet, then restore power to the heater—flip the breaker back on for electric units, or turn the thermostat dial back to your desired temperature for gas.