Should I Flush My Water Heater and How Often Should I Drain It?

Should I Flush My Water Heater and How Often Should I Drain It?

Your water heater is one of those appliances that is easy to take for granted. It’s out of sight, out of mind, and can do its job for years on end without any maintenance at all. You might only think of it when something goes wrong. However, like most appliances, water heaters require periodic maintenance in order to maximize energy-efficiency and extend the lifespan of the unit. A neglected water heater may keep hot water flowing for a few years but will gradually cause your utility bills to creep higher and eventually it will fail altogether.

The best way to protect your investment is to have your water heater serviced annually by a licensed plumber. A good plumber will conduct a full inspection for rust, leaks and other problems, test the thermostat and valves, replace the anode rod to prevent corrosion and flush the tank. 

Periodically flushing out the lime and other sediments in the water heater tank improves the heater’s efficiency and lifespan. In neglected water heaters, sediment can accumulate and calcify, making it difficult to remove. This can get so bad that the entire unit may need to be replaced. But if you flush your tank regularly, you can prevent sediment from causing problems.

All water has some degree of mineral content. If you live in an area with lots of limestone beneath the ground, the groundwater will pick up calcium and magnesium deposits, resulting in “hard” water. Hard water creates sediment in the form of lime scale that settles out of the water and builds up at the bottom of your water heater. With natural gas heaters, it can cause uneven heating on the tank that eventually causes leaks. With electric heaters, scaling can burn out the lower heating element. And in both, sediment buildup can clog the drain valve.

The frequency with which to flush a water heater depends on the size of the tank and the amount of hot water used. It is a good idea to refer to the manufacturer’s instructions. Usually, the more hot water a household uses, the greater the maintenance flushing frequency.

With time, water heater sludge accumulates at the bottom of a tank as minerals, sediment and other deposits settle in the water. Flushing out these deposits prolongs the heater’s life and prevents malfunctions, such as cold burst of water.

If you don’t have access to the manufacturer’s instructions, the following serves as a general guide:

One or two people in a home: Inspect the water heater every six months and drain it every 12 months

Three to five people in a home: Inspect the water heater every four months and drain it every eight months

Six or more people in a home: Inspect the water heater every four months and drain it every six months

You may need to drain the hot water tank more often if your water comes from a well or if your municipal water has abnormally high sediment content.