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Water heater with leaking drain valve

How do you Flush a Water Heater?

Homeowners who have never flushed their water heater might be wondering “why is this important to do?” Removing the sediment and scale that builds up in the tank helps the water heater run more efficiently — prolonging its life. This is especially relevant for homes with galvanized piping, where it is more likely to rust and be in worse condition than homes with copper or PEX pipe.

Mr. Rooter's licensed plumbers recommend performing this task once a year, and it applies to both gas and electric water heaters. For those of you with residential tankless water heaters, check out this article on descaling your heater.

Step-by-step Process to Flush a Water Heater

  1. If you have an electric water heater, turn off the breaker to the water heater. If you have a gas water heater, turn off the gas valve leading to the tank.
  2. Turn off the water valve that supplies water to the tank.
  3. Attach a hose to the brass or plastic drain valve at the bottom of the tank.
  4. Drag the other end of the hose to a drain or hard surface outside. DO NOT let the hose drain in the grass or it will kill the grass.
  5. Once the hose is connected, open the valve, and let the sediment flush out (this may take 30-60 minutes).
  6. After the tank has emptied, you can intermittently turn the cold water back on to flush out any extra sediment that remains in the tank.
  7. When finished flushing it out, close the drain valve and turn the water back on so that the tank can fill.
  8. Once the tank has been filled back up, electric water heaters need the breaker flipped back on. And for gas water heaters, turn the gas valve back on and relight the pilot light.

There you have it – you are all done!

Potential Issues?

Draining a water heater is generally a maintenance task that homeowners can complete. But there are still a few issues you can run into:

  • Be sure to keep an eye out for continuous leaks near the drain valve before and after this process. We tend to see this more often in heaters with a plastic drain valve instead of brass. 
  • Always make sure to turn off the breaker so you avoid any chance of burning out water heater elements.

Call the Professionals

If you do find yourself dealing with a water heater problem or would simply prefer to have an expert plumber take care of it, call Mr. Rooter Plumbing, and we will send a professional right away. Whether you need service late on a weeknight or first thing on a weekend morning – we can provide emergency service and there is never an overtime charge!