How to Clean an A.O. Smith Electric Water Heater

Over time, the inner tank in a water heater can get clogged and corroded from minerals present in water.

Flushing the Tank

The minerals and deposits find their way into sinks and showers and can cause further damage. A little time and a few tools can help keep your AO Smith water heater clean and in good condition.

Your AO Smith electric water heater will need to be disconnected from the power source before you clean the interior of the tank. Flip the breaker, and unplug the heater. Shut off the water using the water shutoff that is generally located above the water heater.

Along the bottom of the tank, the water heater has come equipped with a threaded flush valve with a handle that turns. Connect one end of the garden hose to this flush valve, and run the garden hose to a place outdoors where the heater can drain.

Turn the valve to open, and allow the full contents of the water heater to drain into the hose and outdoors. Turn the flush valve off.

Open the water valve at the top of the heater, and allow the tank to fill with water for 2 to 3 minutes before again cutting the water supply.

Again turn the flush valve on, and allow water to flow outside until the tank is empty. These steps should be repeated until the water running outside is free of discoloration and mineral buildup.

Things You Will Need

  • Garden hose
  • Screwdriver


  • Commercial tank additives are available that claim to clean the water tank of debris. Check with your water heater's warranty before using these additives. If the flush valve gets clogged, it is generally due to mineral buildup in the valve itself. Gently clear the valve with a screwdriver.


  • Water that flows from the heater is hot. Drain in a safe place away from materials that will be harmed with the hot runoff. Children should be kept away from the drainage area.


About the Author

Lauren Thompson lives in Kansas City, Missouri and works as both a writer and freelancer. Her background is in technical and spec writing for the information technology industry, as well as financial services. She also writes opinion and editorial articles for KCParent and Parents Edge, specializing in entertainment, food and political realms.