Draining a Water Heater

Draining a Water Heater

Water heaters do benefit from periodic preventative maintenance. There aren’t many things worse than an unexpected cold shower. A little bit of upkeep such as draining your water heater can ensure efficient and safe operation of your tank and extend its life span. Please refer to the maintenance section of your installation and operation manual which can be found here.

Reasons for Draining a Water Heater

  • Discolored Water

    • A water heater tank is the primary water reservoir in the home. (Toilet tanks also act as reservoirs.) Any contamination that exists in the incoming water will finally settle in the storage tank.
    • The water heater tank acts as a water filter, and the many thousands of gallons
      that pass through the system over the years deposit all the rust or other foreign particles into the tank. It is for this reason that a water heater should be periodically flushed out through the drain valve provided at the bottom of the heater.
    • Experience shows that a great majority of so-called rusty water conditions are not rust, but sand and clay sediment which finds its way into the water heater through well systems utilized in many homes, or from major water main breaks which would result in great quantities of clay and mud getting into the main system while the mains are under repair.
  • Milky or Cloudy Water

    From time to time, homeowners may discover milky colored water in their lines. This can occur in hot water as well as in cold water lines. It can happen with new or recently installed water heaters as well as with water heaters that have been installed and operating for long periods of time.

    This condition can be caused by various factors:

    • Aerators at faucets introduce additional air to the water and when collected in a glass the agitated water appears milky or cloudy.
    • Additional air can be introduced to city water supplies at the pumping station when air is pumped into the water mains to increase pressure.
    • In private well water systems, artesian pressure can cause air entrapment.
    • When water utility companies switch from one deep well source to another, excessive air can develop in the system.
    • Underground temperature changes in water sources (particularly in spring and fall) cause air to expand.

A possible remedy for any of the above conditions is to drain the tank and thoroughly flush the inside surface.

How to Drain a Water Heater

According to The Air-Conditioning, Heating and Refrigeration Institute (AHRI):

Sediment build up in the tank can reduce your water heater’s energy efficiency and also clog your water lines. Avoid these problems and increase the life of your unit by flushing the tank each time you check the pressure relief valve.

To Check the Pressure Relief Valve:

  1. Turn off the electricity to the water heater or turn the gas switch to pilot.
  2. Shut off the cold-water inlet to the water heater.
  3. Position the bucket to catch water from the pressure relief valve.
  4. Pull the trip lever on the valve. You should hear a slight rush of air or see some water and vapor exit through the pressure relief valve. If you don’t, drain the tank and replace the valve.

To Flush the Tank:

  1. Turn off the electricity to the water heater or turn the gas switch to pilot.
  2. Shut off the cold-water inlet to the water heater.
  3. Connect a garden hose to the tank’s drain valve.
  4. Locate the draining end of the hose in an area that won’t be adversely affected by the scalding hot water.
  5. With the pressure relief valve open, you can now open the drain valve and allow the tank to drain completely. Draining the tank completely ensures that you have removed all possible sediment.
  6. Close the tank drain valve, disconnect the hose from the valve and close the pressure relief valve.
  7. Open all the hot water faucets in the house and turn on the cold-water inlet to the tank.
  8. Close each hot water faucet as water begins to flow from it. After all the faucets are closed, turn on the electricity to the water heater or turn the gas switch to “run.”
Although there may be some simple maintenance checks you can do yourself, we
highly recommend you have a plumbing professional help. Need a pro? Find one here.
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