Water heater.

How to Flush Your Water Heater

An important part of owning and maintaining a traditional water heater is flushing it. In this blog, our plumbers explain the reasons for flushing your water heater and share the steps to do it yourself.

Benefits of Flushing Your Water Heater

Flushing your water heater is a necessary maintenance task that should be completed every year--but why is it so essential? Hard deposits like limescale, magnesium, and calcium get picked up by water as it flows through the water system and into our homes. Also called hard water, these minerals accumulate and create a buildup that affects the efficiency of your water heater.

When to Flush Your Water Heater

Some recommend flushing your water heater every six months, but if you live in an area that has softer water, you’ll likely be okay only doing it once a year. Water in San Jose falls under the ‘very hard’ side of the scale due to the mountainous regions we get our water from, so older tanks may need to be flushed more frequently than newer installations.

9 Steps to Flush a Water Heater

Below are our instructions for draining and flushing the tank of a traditional water heater.

1. Cut the cold water supply

The water supply shut-off is most likely located where the main water supply line enters your house. If you can’t find it there, look for the supply shut-off valve on your water softener.

2. Turn off water heater thermostat

Turn off the thermostat to prevent the heater from turning on when the tank has been emptied. If the heater were to turn on without water to heat, it could cause damage to the tank. If you have a gas-powered water heater, make sure you close the gas supply valve before moving on.

Tip: Some water heaters have a ‘vacation mode’ you can use as well.

3. Connect a drain hose

Connect a garden hose to the drain valve (located near the bottom of the tank). Let the opposite end of the hose coil into itself, forming a small circle--this will help to catch the sediment as the water drains from the tank. To protect your foundation from flooding, you can place the open end of the hose into a bucket or drain or just make sure to extend the hose past the foundation.

4. Open all hot water faucets in your home

Opening the faucets helps to create a vacuum through your water supply lines--allowing the tank to drain faster.

5. Start draining your tank

Open the drain valve to release the water. Gravity will do most of the work, but be sure to supervise the process so you can get a good idea of how much sediment has accumulated over time (this can help you determine how often you may need to drain the tank in the future).

Tip: The water flowing from the tank can still be hot, so keep young children and pets away to protect them from burns.

Troubleshooting: You may open the valve and find that no (or very little) water comes out. This could be caused by sediment blocking your drain valve. Open the temperature-pressure release to relieve pressure in the tank and drain any water sitting in pipes. Once you’ve done this, use a shop vac to try and suck the blockage out of the drain valve.

6. Rinse your tank

When the tank is fully drained, it’s time to rinse any loose sediment left behind. Turn the cold water supply on and let the water run through the tank and out the hose for a few minutes. When the water coming out at the end of the hose runs clear, you’re ready to move on. Turn the water supply back off for now.

7. Clear the drain valve

Disconnect the hose from the drain valve. To prevent sediment buildup around the valve, use a shop vac to suck out any sediment leftover in the drain valve. Once these areas are clear, you can turn your cold water supply on again.

8. Clear the faucets

To prevent air from becoming trapped, leave all hot water faucets open as your tank refills. Don’t worry if you see brown or discolored water flowing from the taps--this is caused by leftover sediment or rust that should clear out in a matter of minutes. When the water runs clear, you can turn the hot water faucets off.

9. Clean up

We’re almost done! Typically the tank in your water heater will take 30-40 minutes to fully refill (though this varies based on the size of your tank). While the tank is refilling, reset your water heater thermostat to whatever temperature is comfortable for you and your family. The maximum recommended temperature is 140 degrees, but you can save a lot of energy and prevent accidental scalds by setting the temperature to 120 degrees instead. If your home has a gas-powered water heater, remember to reopen the gas supply valve and relight the pilot light.

You’ve just drained your water heater! This task can seem complicated from the outside, but once you’ve done it a few times, it’ll feel like second nature. However, if you’re hesitant and would feel more comfortable with a professional taking care of the task, give EJ Plumbing a call. Our plumbers can assist you with all your water heater installation, repair, and maintenance needs.