How to flush a tank water heater

Over time, minerals from hard water settle at the bottom of a tank-style water heater. That sediment can reduce efficiency, create popping noises, and shorten the life of the unit. Flushing the tank helps clear some of that buildup.

Why flushing helps

• Reduces sediment that insulates the burner or heating element from the water
• Can improve recovery time and hot-water consistency
• May reduce rumbling or popping sounds during heating cycles

Basic overview (tank heaters)

1. Turn off power (electric breaker) or set the gas control to “pilot/vacation” as directed by the manufacturer.
2. Shut off the cold-water supply to the heater.
3. Connect a hose to the drain valve and run it to a floor drain or outside.
4. Open a hot-water faucet somewhere in the house to relieve pressure, then open the drain valve.
5. When the tank has drained, briefly open the cold supply to stir remaining sediment, then drain again.
6. Close the drain, remove the hose, refill the tank fully before restoring power or gas.

When to call a pro

Skip DIY if the drain valve is stuck or leaking, you smell gas, the heater is very old, or you’re not comfortable working around water and electricity/gas. Essential Plumbing can flush, inspect, repair, or replace tank water heaters and tankless water heaters — call 317-899-9009.

This guide is general information for homeowners. Always follow your manufacturer’s instructions.