Treatment of Calcium Deposits in Water Heaters

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Hot water heaters should be flushed at least once every three months.

If you are hearing weird banging noises coming from your water heater, chances are it is because you have calcium deposits built up in the heater. Calcium deposits are hard mineral deposits that latch on to your heating elements and other parts of your water heater often due to hard water. There are ways you can not only treat the deposits, but also keep your water heater running efficiently.


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Checking your Water Heater

Top of the water heater. Clean sediment by adding vinegar or commercial acid and flush.

You should check your water heater first to determine how much calcium deposits are in the heater or if it is just sediment. Turn the heater and the cold water supply off. Place a water hose to the drain valve and keep the rest of the hose away where hot water can safely exit. Open the drain valve and check for any small or large white particles. If you see these, then you have calcium deposits.


Let air into the heater by disconnecting the cold water inlet pipe, which is usually on the top of the heater. Ensure the tank is empty and close the drain. Pour a gallon of vinegar, acidic tub and tile cleaner or other commercial lime cleaner, one cup at a time, pausing after each cup, into the cold water inlet pipe. Pausing between cups prevents gas build-up.

Wait a few hours and drain the tank. The cleaner should have dissolved all or most of the deposits. You can check if the cleaner is still working by using a small plastic bag and wrap it tightly around the cold water inlet pipe. If the bag inflates, wait a bit longer as this means the cleaner is still working on the deposits.


Flushing the Water Heater

A well-used water heater may need flushing more often.

Connect the cold water inlet pipe, turn the heater on, and open the cold water inlet valve to flush the heater. Open the hot water faucet that is nearest to the heater and close the drain to let the heater fill. When you see water coming out of the faucet, open the drain, and let the heater rinse.


Wait until the water runs clear and there are no bubbles before you close the drain. To drain air out of the heater, turn all the hot water faucets on. Then turn the heater back on.

Why Remove Deposits

If you notice your water bills creeping up and your hot water heater is not working at its best, calcium deposits and sediment are the reasons. When deposits are on the tank bottom or elements, it interferes with heat transfer into the hot water, according to This results in high costs and longer waits for hot water.

You can prevent deposits by flushing your water heater every few months as well as purchasing a water softener and attaching it to you incoming water supply.


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Kathy Eastwood

Kathy Eastwood is an avid freelance writer and works full time as a photojournalist for a weekly tabloid at West Point, N.Y. She has over seven years experience in writing professionally and in writing Web content. She attended New Paltz College in New Paltz, N.Y.