How to Flush Your Water Heater to Remove Sediment

Sediment is the silent enemy of the modern water heater. Over time, minerals found in your water supply settle at the bottom of the tank, creating a calcified layer that forces your heating elements or burners to work overtime to penetrate the sludge. This not only spikes your utility bills but also accelerates corrosion and shortens the lifespan of the entire unit. Flushing your tank once a year keeps the heat transfer efficient and prevents that annoying popping or rumbling sound when the water heats up. While the process involves working with hot water and valves, it is a straightforward maintenance task that anyone can master in an afternoon. Done well, the water runs clear and your heater operates silently for another season.

  1. Kill the Power First. If you have an electric water heater, flip the circuit breaker in your electrical panel. For gas models, turn the control knob on the heater to the 'Pilot' or 'Off' position.
  2. Stop New Water From Entering. Locate the cold water inlet pipe at the top of the heater and turn the valve handle clockwise until it is fully closed. This stops new water from entering the tank while you drain it.
  3. Route Water to Drain. Connect a standard garden hose to the drain valve located at the base of the tank. Route the other end of the hose to a floor drain, a basement sump, or safely outside.
  4. Release the Sediment. Use a flathead screwdriver or the built-in handle to open the drain valve slowly. Watch the water coming out of the hose; you will likely see cloudy or rusty water containing small mineral flakes.
  5. Repeat Until Water Runs Clear. Once the initial water has drained, briefly turn the cold water supply back on to stir up any remaining debris at the bottom of the tank. Repeat this until the water flowing out of the hose runs perfectly clear.
  6. Restore Power and Heat. Close the drain valve, disconnect the hose, and turn the cold water supply back on. Once the tank is full and water flows steadily from your hot water faucet, turn your circuit breaker or gas pilot back on.