Water heaters can lose their efficiency resulting in higher heating cost and higher water bills. The reason for them losing efficiency is sediment in the tank building up which is impeding heat transfer and absorbing some heat as well. This sediment can also cause damage to your water heater or cause clogs in your water lines. The answer to this problem is a simple flushing of your water heater. It’s typically recommended to have this done once a year.

Caution: A professional should be called to perform maintenance and inspect the health of your water heater, if you are not comfortable in such tasks or have an older water heater that might not have obvious signs of damage. Check with your manufacturer’s warranty regarding maintenance to ensure you won’t void your warranty performing the maintenance yourself. Before performing the maintenance below, know where your main water shut off valve is and it’s in working order in the event something goes wrong to prevent further damage due to water damage.

Steps to flush the water heater

Turn off or turn down the heater’s heating system or gas to prevent the water heater from turning on and heating an empty tank. If you have a gas water heater this could be setting the thermostat to off or “pilot” or “vacation mode” and in the case of an old system, it may require turning off the gas to the water heater. You may have to relight the pilot light on older gas water heaters if the gas is turned off, and you should know how to relight it and where it is located. If it’s an electric water heater, you can turn if off via a switch or unplug it or you may have to turn it off via the circuit breaker if there isn’t a way to turn off the flow of electricity to the water heater.

Turn off the water source to the water heater. In some homes this means the main water valve to the home, others may have a shutoff valve near the water heater. You may have a filter or system such as water softener that may have a shut off valve available.

Connect a garden hose to the tank’s drain spigot near the bottom of the tank and remember not to overtighten. Place the other end of the hose to an area that can handle the amount of water and the heat from currently hot water in the water heater tank.

Note: If you don’t want to worry about draining hot water from the tank, turn off only the heating source and leave the water valve on and turn on a hot water faucet in your home to allow the hot water to drain from the tank down the sink drain and water heater’s water will be replaced by cold water. After you have found the water temperature is cool enough, turn off the water source to the heater as the previous step.

Turn on at least one hot water faucet in your home to allow air to flow to prevent a vacuum from forming and not allowing the water to drain from the hot water tank. Open the drain valve to allow the tank to empty through the hose. Check with your manual as to how to open the drain valve as it can vary depending on model. Listen for the sound of water running, if you don’t hear water and don’t see any draining at the end of the hose, you may have something preventing the air from flowing such as a backflow preventer or sediment has clogged the drain and you will need to open the pressure release valve to allow air into the system. This is also an opportunity to test your pressure valve as suggested below. Most  When you are sure water is coming out, check the hose to ensure there isn’t a leak along the way and the other end is still draining in the spot you have chosen and the water draining isn’t going to overflow the draining area.

Once the water is draining, observe the water’s color and clarity. You want the water to be fully clear or mostly clear at the end of the draining. The next thing is to ensure the remaining sediment on the bottom of the tank gets flushed through by turning on the water valve to the tank to allow water to rush into the tank with the drain valve open. Sometimes it helps to turn on the water for about 15 seconds and turn off the water and wait for a few minutes and do this again a few times to completely remove some sediment that is stuck on the inside. Observe the water draining to be sure the sediment is gone, and the water being drained is clear. Turn off the water to the tank when you are finished flushing the system.

Now that the system is cleaned out, it’s time to put everything back:

  • Close the drain valve and remove the hose.
  • Close the pressure valve (if you opened it, if not still check that it is closed).
  • Turn the water back on to the water heater.
  • Open the hot water faucets around the house to ensure the water flows and there is no air trapped. You may see sediment coming from the faucets, just wait until the water is clear. Once it is clear, turn off the faucet.
  • Turn on the heating source, which may involve reignited the pilot light if it’s a gas water heater and it blew out.Be sure to turn it on only after the tank is full. Turning on an electric water heater without the tank full will cause the heating element to burn out.


You may want to make a note somewhere of the date you performed this service or had this service done so you can keep a maintenance record for yourself and possibly your insurance. This will help remind yourself when it was done last year and if there are some issues with your water heater before a year is up, there may be more serious issues with your water lines or water heater that a professional should look at before it becomes an expensive repair with water damage also involved.