Water Heater Maintenance

If you’ve been away from your home for a long time, you might want to check your water heater when you return.

Manufacturers recommend periodically flushing sediment from your storage-type water heater. Residents in areas with high mineral content in the water should flush more often.

Most sediment in water heaters develops when minerals settle after the water heats. Sediment in water heaters also can contain sulfur compounds that can cause odors in the water.

Here’s how you can flush sediment from a water heater:

  • Be cautious — the water in the heater might be extremely hot and capable of causing burns.
  • Follow the manufacturer’s instructions for specific procedures on how to flush the water heater. These instructions are generally found in the manual included when the heater was purchased. You might also find them on the manufacturer’s website. If you are unable to find the manual or information on the website, the procedures that follow might work.
  • If you have a gas water heater, set the gas valve to“pilot” to prevent the burners from coming on while you are flushing it.
  • If you have an electric water heater, be sure to turnoff the circuit breakers to the heater. If the water level drops below the heating elements and the thermostat turns them on, the heating elements could be damaged.
  • Connect a garden hose to the drain valve at the bottom of the tank. The water could be very hot — make sure the outlet of the hose is in a safe area away from pets and children.
  • Close the shut off valve on the cold water inlet to the water heater.
  • Carefully open the temperature/pressure-relief valve at the top of the tank by lifting the lever. Leave the valve open.
  • Open the drain valve at the bottom of the heater to allow the water to flow out through the garden hose. If sediment is clogging the drain valve, try closing the temperature/pressure-relief valve and turn the cold inlet valve back on to “power-flush” the sediment.
  • In some cases, the sediment hardens into large chunks that can block the drain valve. If this occurs, wait until the water in the heater has cooled, remove the garden hose from the drain valve, remove the valve if necessary, and use a long screwdriver to break up the clog.
  • When the garden hose runs clear, you’re finished.
  • Close the drain valve at the bottom of the tank and remove the garden hose.
  • Close the pressure-relief valve at the top of the tank if it is still open, and open the hot water faucets in the highest part of the house. Slowly turn on the cold inlet valve for the hot water.
  • Let the hot water faucets run in the house until the air bubbles stop coming out, then fully open the cold water valve to the hot water heater. Make sure your pressure relief valve and drain valve aren't leaking.
  • Turn the heater back on. With a gas heater, relight the pilot light if it has gone out.