How Often Should I Drain and Flush My Tank Style Water Heater?

It is a good idea to flush your water heater once a year.

Many people are unaware that a water heater should be flushed at all. I’ve gotten blank stares by homeowners when the idea is mentioned.

Despite this common lack of awareness, homeowners have experienced a water leak at the bottom of the water heater or reduced water flow in the house.

These conditions are usually the symptoms of not flushing the water heater during routine maintenance.

What happens inside a water heater?


Water heaters build up scale and sediment inside over time. This build up is due to the minerals and sediment in the water that supplies the water heater. It is also due to the fact that the water heater is constantly maintained at a hot temperature. This heat helps the dissolved particulates in the water to form a solid-state hardness on the metal surfaces inside the water heater. This buildup is widespread throughout the water heater. The largest deposits are often found at the bottom of the water heater where they tend to settle. The deposits usually bond together forming a large mass of hardened sediment almost like a large chunk of concrete.

How does flushing the water heater help?


Flushing the water heater reduces the amount of hardened particulate buildup over time. This maintenance practice prevents sediment from collecting and forming large masses of formations. This mass of sediment will effectively reduce the water storage capacity of your tank size. As a result, your water heater will have to heat water more frequently.

The large sediment mass is also harmful to the tank itself as this sediment is likely to be corrosive to the inner metal surfaces. This will reduce the longevity of the water heater.

Keeping these large formations of sediment from occurring is beneficial for 2 reasons:

  1. It improves the efficiency of your water heater,
  2. It reduces the likelihood your water heater will fail and start leaking.

How do you flush your water heater?


It is not difficult to flush your water heater. Simply follow these steps:


  1. Turn off the heat source – whether it is electric, gas, or oil.
  2. Close the cold water supply valve to the off position.
  3. Connect a garden hose the drain valve at the bottom of the water heater. You can also use a pump but make sure to prime it.
  4. Open a faucet on the hot water side only or otherwise create a vent point.
  5. Open the drain valve. Some have handles and some require a screwdriver.
  6. Drain the water from the water heater.
  7. Next, open the cold water supply valve for short 15 second bursts several times. This will disturb the sediment that has been collecting in the water heater.
  8. Repeat this flushing until you remove the sediment and you have clear water coming out of the drain hose.
  9. As a last optional step – you can fill the water heater all the way back up with the hot water faucet / vent and drain valve closed.
  10. Then drain the tank 1 more time. This will allow a full body of water to push out any stubborn sediment.
  11. Now you can re-fill the water heater. Make sure to close the hot water faucet side / vent point, and the drain valve. You may also fill the tank with the hot water faucet side open to allow the air in the tank to escape while you fill the water heater. Turn it off once you have a solid stream of water coming out of the faucet.

That’s it – Your Done. Good Job!

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