How Often Should I Flush My Water Heater

I flushed my water heater last weekend. No, I wasn’t playing poker, and this was certainly not a gambling thing like I usually do. I was just performing general maintenance to increase the lifespan and energy efficiency of a major home appliance. On the contrary, not flushing a water heater tank annually is a gamble that increases the odds of premature failure. And nobody wants premature failure. However, early failure chances increase if you have an electric water heater, where sediment will bury and corrode the heating element inside the bottom of the tank.

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Home Repairs

Flushing is an annual chore relatively easy to do and doesn’t take too much time while 40 or 50 gallons of water drains and refills the tank. Flushing removes calcium or other mineral sediment build-up on the bottom of the tank that otherwise reduces capacity and insulates the water from the bottom fired gas burner or in-tank electrical element, reducing heating efficiency. Annual maintenance is essential is an area such as Salt Lake City, where the water is somewhat alkaline.


How To Flush Your Water Heater

Here’s the simple setup. Modify the water heater’s primary compression drain valve outlet at the bottom of the tank, replacing it with a quarter turn ball valve with hose threading to allow sediment to pass through without restriction. Then, all you need is to hook up a short length of garden hose from the valve to a nearby floor drain.


Now, here’s the flushing procedure, to be followed when there is low household demand for hot water. First, and very importantly, turn off the gas supply or electrical power to the water heater, so the empty tank or element will not burn. Now, shut off the house water supply valve from the water meter. Later, open an upstairs sink hot water faucet or two to enable air to replace water draining out of the lines and tank. After a garden hose is connected from the water heater drain outlet to a basement floor drain, open the drain outlet ball valve. Monitor water flows out of the hose. Hot water should start to flow at least moderately. If water flow is a mere trickle, there may be sediment blocking the ball valve. Turn on and off the house water supply valve several times to break up and jet force sediment through the valve.


After water ceases to flow out of the hose, the water heater is drained, and most sediment should be gone. Now, close the drain ball valve, and open the house water supply valve to fill the tank. Don’t forget that when the tank is full, the air in the tank and water lines is replaced by water which will come out of the sinks hot water faucets, so shut them off. Lastly, turn on the electrical power or gas supply to the water heater. On most gas water heaters, the pilot light will need to be relit. Hot water recovery time will be about an hour.


Now you’ve got peace of mind in the assurance that you’ve done what you can to prolong the life of your water heater, and cut down on your electrical or gas utility bill.

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