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Water Heater Maintenance: How to Maintain Your Water Heater by Flushing

Water Heater Maintenance Schedule

Once every two months:

Inspect the water heater. Check for water leaks, either at plumbing joints or, for tanktype water heaters, coming from the tank itself. Check all plumbing joints for excessive or unusual corrosion. If the water heater is gas-powered, check the condition of any flex hose and the couplings (including smelling for gas leaks), and make sure no flammable materials are near the area of combustion. On a tank-type water heater, test the temperature and pressure relief valve to make sure it opens and closes freely. Turn on a nearby hot water tap and listen for unusual sounds (especially hammering or crackling) that might indicate a more serious water heater problem.

Once every six months to a year:

Flush your water heater by draining several gallons of water through the drain valve. This will remove any sediment that has built up inside.

Once every year:

After the water heater is two or three years old, the anode rod should be removed and inspected once every year. Some pitting and surface corrosion are normal and to be expected. Large chunks of metal coating missing from the surface indicate that it should be replaced.

Water Heater Maintenance: Flushing your water heater

Flushing a water heater tank is an important part of water heater maintenance and should be performed once every six months (particularly in hard water areas) to a year. It involves, simply, draining several gallons of water from the bottom of the water heater tank, through the drain valve, in order to draw off sediment —minerals and other minute solids that are found in all water systems—that normally accumulates at the bottom of the tank over time. That sediment impairs the water heater’s performance and shortens its lifespan, so this flushing should be done regularly. Draining the hot water tank is also necessary to perform some repairs.

WARNING: Water heaters are typically factory-set to heat water to 125° F, which is hot enough to inflict first degree burns on skin on contact. When turned all the way up to maximum temperature (which can be anywhere from 160ºF to 190º F) serious injuries can result from even indirect contact with the water. Always take precautions to avoid coming into contact with heated water.

The first step is to power down the gas valve — gas at the CONTROL KNOB to VACATION. Keeping in mind that the water inside the tank is hot and will remain so for quite some time even after the gas valve is turned to vacation, it is best to use some of the hot water or to wait several hours to allow the water in the tank to cool before proceeding with the flushing.

When you’re ready to flush the water heater, turn off the water supply at the cold water shut off valve. Open a hot water faucet that is nearby and is no lower than the level of the water heater, and leave it open. This will allow air to enter the tank as it empties. Securely connect an ordinary garden hose to the drain valve located near the bottom of the water heater. Make sure that the hose is long enough to reach a drain or sump pit (and it should at no point be higher than the drain valve since the draining process will be gravity-fed). Once the hose is in place, open the drain valve. It will have either a dial or a slot for a flathead screwdriver that you will have to turn counter-clockwise to open. At this point, the tank should begin draining. After a few gallons have drained, collect some of the water in a bucket or run it through a screen to inspect it for sedimentation amounts.

If very little sediment is found and the water flowing from the tank is otherwise clear flush several more gallons and then stop the process. Regularly flushing the tank every six months will typically produce this type of result. If heavier sedimentation is found, however, continue to drain the water, occasionally turning the cold water supply back on to help stir up and remove any materials still in the tank. Continue doing this until the water flowing from the tank is clear and sediment-free.

Once your water tank has been completely flushed, or you have finished making any repairs, you can refill the tank by closing the drain valve and turning the water supply back on. Do not turn the gas valve from vacation until the tank is completely full. Check the hot water faucet you opened earlier. When water is coming out of it at full stream you know your tank is full and you can turn the power back on.

The only time it should be necessary to completely empty a tank is when the drain valve needs to be replaced, or when the water heater itself needs to be replaced. To do this, follow the same procedures as with flushing, but leave the drain valve open until no more water flows from it.