How to Maintain a Water Heater in Three Easy Steps

Construction: Fixing a hot water heater
Jodi Jacobson / Getty Images

A water heater typically lasts between 8 and 12 years, but only if it is maintained properly. A simple three-step annual maintenance plan will extend the life of the water heater.

If you're just going through routine servicing, there's no need to call a professional to complete the job for you. With a screwdriver and a bucket, a homeowner can usually complete servicing the water heater on their own. Before you start, turn off the power (for electric water heaters) or the gas supply (for gas heaters) for safety:

  • Electric: Switch off the circuit breaker for the water heater in your home's service panel (breaker box).
  • Gas: Turn the pilot knob (located on the water heater's gas valve/thermostat) to the OFF position.

Do a Mini-Flush

Prevent rust and corrosion by removing sediment from the bottom of the tank, a task that also improves the energy efficiency of the unit. Although a complete flush of the water heater tank is best, it requires shutting down the water heater. A mini-flush works well, takes a fraction of the time, and can be done while the water heater is running:

  1. Place a bucket under the drain valve found near the bottom of the water heater tank.
  2. Turn the valve counterclockwise to release 1 to 2 gallons of water into the bucket. Some drain valves have a handle, while others have a short stem with a slot for a flathead screwdriver. Warning: The water will be very hot, so take care to avoid burning yourself.
  3. Close the valve by turning it clockwise.

If the valve won't open, contact a plumber to perform maintenance.

water heater drain valve

Test the T&P Valve

The temperature and pressure (T&P) relief valve is a critical safety feature of your water heater. It senses dangerous pressure buildup or excessively high temperature inside the water heater tank and automatically opens to relieve the pressure. Without an operational T&P valve, a water heater is at risk of explosion. Therefore, water heater manufacturers recommend testing the T&P valve once per year.

The T&P valve might be located at the top of the heater tank or in the side wall, and it has a discharge tube that extends down toward the base of the tank. To test the valve:

  1. Place a bucket under the end of the discharge tube connected to the T&P valve.
  2. Lift up on the lever of the valve to open the valve manually. This will release hot water through the discharge tube and into the bucket. Warning: The water is very hot, so take care to avoid skin contact.
  3. Let the water flow for a few seconds, then let go of the lever and allow it to snap back into place, shutting off the water.

If the T&P valve does not open and release water,​ or if it leaks after the test, the valve must be replaced.

water heater t and p valve

Dial Down the Temperature

Water heaters are typically installed at a preset temperature of 130 to 140 degrees Fahrenheit. However, the U.S. Department of Energy recommends a setting of 120 F for most households, estimating that this can reduce energy costs for water heating by more than 5 percent. Lower temperatures also reduce the risk of scalding and slow the accumulation of mineral deposits in your water heater tank.

To lower the water temperature on a gas water heater, turn the temperature dial on the heater's gas valve to 120 F.

To lower the water temperature on an electric water heater, you might need to remove a small metal panel covering the thermostat:

  1. Turn off the power to the water heater by switching off the appropriate breaker in your home's breaker box.
  2. Remove the thermostat access panel and adjust the temperature to the desired setting. This might require a flathead screwdriver.
  3. Replace the thermostat cover and turn the power back on at the breaker box.

Many electric water heaters have both an upper and a lower thermostat. If yours has two, adjust the lower thermostat to the same temperature setting as the upper.

water heater thermostat