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After a hard day at work or a trip to the gym, almost everyone enjoys a nice, hot shower, but if you don’t take care of your water heater by draining it at least once a year, sediment can develop in the bottom. When a layer of silt covers the bottom of the water heater, it can limit efficiency and cause damage, such as a broken heating element.

If you frequently flush the water heater and expansion tank, you may never have to deal with sediment buildup. Follow these simple steps to discover how to flush and clean a water heater to prolong its life and maintain its heating effectiveness.Table of Contents

Turn off the power supply

A water heater’s aim is to heat a significant amount of water using either gas or electricity as a fuel source. To avoid causing damage to the water heater, turn off the fuel source before flushing it.

Look for a thermostat on the outside of your gas water heater if you have one. It features a red knob and is usually situated where the gas line attaches to the unit. Make a mental note of the temperature control setting, then adjust the thermostat to the lowest setting, which should be labeled “Pilot.”

If your water heater is electric, you must switch off the power at the fuse box or breaker box. Turn down the branch breaker in the breaker box that is assigned to the water heater. If you are unsure which branch breaker is allocated to the water heater, turn off the main switch to turn off power to the entire house.

Remove the fuse that is assigned to the water heater from the fuse box. If you don’t know which fuse is allocated to the water heater, you can turn off the electricity to the entire house by either turning off the main switch or disconnecting the main fuse for the house. Keep in mind that because the electricity will be turned off throughout the house, you will need to operate with a flashlight or work lamp.

Turn off the water heater the night before to allow the tank water to chill. Not only does this lessen the risk of being burned, but it also allows you to use the water in the tank for something other than draining it into the sewer.

Turn off the water supply valve

The water heater loses its ability to heat the water in the tank when the heat source is turned off. To mitigate the risk of burns, it is advisable to activate a nearby faucet and allow the hot water to flow into the sink until it is substituted with cool water. While not mandatory, it is advisable to work with cold water as it is a safer option.

Once the majority of the hot water has been replaced with cold water, turn off the valve that supplies water to the building. This valve should be installed near the top of the tank, where the cold water pipe enters.

It is not necessary to turn off the propane or natural gas supply valves during this process. The water heater will not heat if the thermostat is set to the lowest setting.

water heater flush

Connect the drain valve with a garden hose

Determine the location of the drain valve at the base of the water heater and connect a garden hose to it using channel locks. The drain valve resembles a standard hose bib, similar to an outside faucet, except it may be made of plastic rather than metal. If you can’t find it right away, it could be buried beneath a removable cover.

Connect the garden hose to the drain valve and extend the other end to a location where the tank may drain safely. Remember that if you don’t allow the water to cool down over night after shutting off the power, you’ll be dealing with searing hot water.

Choose a location that will not be harmed by the force, temperature, or amount of water, and also wrap a cloth around the drain valve as well as the hose connector to protect yourself from hot water and to prevent any water from spraying from the connection.

Turn on a hot water tap that is nearby to prevent a vacuum within the water lines from trapping water in the tank. If you already opened a faucet to replace hot water with cold water, simply leave it open.

To drain the water, open the drain valve

The garden hose should be firmly linked to the drain valve, with the other end in a suitable drainage site. To begin emptying the water from the tank, turn on the drain valve. The pressure-relief valve at the top of the water heater can be cautiously opened to improve the flow of water through the drain, but a bucket should be placed beneath the discharge pipe to catch any water before it drains into the floor.


If you did not let the water cool or replace the majority of the hot water with cold water before draining the tank, the water and air inside the tank are extremely hot. Avoid coming into contact with any water or steam that has been released from the pressure-relief valve. To limit the risk of burns, it is recommended that you use gloves and a face protection.

Because the drain valve may be old, take care not to strain the fixture. If it appears to be seized, do not just increase the force. You could cause a forceful spray and deluge of scalding water if you break the valve.

A defective drain valve is a job best left to a seasoned professional or water heater specialist, so if you encounter this issue, you may need to postpone the job until the valve can be replaced. If you think you can handle the valve replacement on your own, keep in mind that if you rent your water heater, the rental company may require you to hire a qualified technician or plumber.

Examine the water

The objective of flushing the water heater is to eradicate any sediment that has accumulated at the bottom of the tank. Therefore, after draining the water heater for approximately 10 to 20 minutes, proceed to fill a bucket with water. Let the bucket remain undisturbed for approximately 60 seconds, then inspect the water to determine if it is transparent and if any solid particles have settled at the bottom.

If the water is hazy or there is sediment at the bottom of the bucket, you must drain the tank again. After another 10 minutes of draining, repeat the test. Repeat until the water is clean and there is no silt in the bucket.

Remove the garden hose and close the drain valve

Shut the drain valve and detach the garden hose once the water is clear and devoid of any particulate matter. Ensure that the end of the hose remains elevated until it is outside or positioned over a drain. Do not shut off either the pressure-relief valve or the hot water valve in a nearby sink or bathtub. Both the valve and the faucet will remain open to facilitate the elimination of air from the pipeline.

Turn on the cold water valve

Keep the hot water valve in your nearby sink or bathtub open to assist bleed air from the water line. Open the water supply to allow the tank to fill. As it fills, the air in the tank’s top is progressively driven out through the open faucet and the pressure-relief valve.

Turn off the electricity until the tank is full. When the tank is full, you will be able to tell because water will be flowing at full pressure via the open faucet. It is now safe to turn on the water heater’s electricity or return the thermostat to the initial setting for a gas water heater.

Close the pressure-relief valve and turn off the open faucet, then wait 20 to 30 minutes. Check the temperature of the water at the nearest faucet.

FAQ’s About Water Heater Flushing

Can I flush my own water heater?

Simply switch open the drain at the bottom of the tank to flush it. Allow it to run for a few minutes, or until the water coming out of your hose is clear. This could take some time. While the water may be clear and not brown, it may still include silt.

How long does a tank water heater take to drain?

Open the drain valve on the hot water tank. Allow the water to flow from the garden hose. Depending on the size of the tank, this could take 30 to 45 minutes.

What happens if your water heater isn’t flushed?

The longer you go without a drain and flush, the more sediment and minerals build up at the bottom of the tank. This eventually leads to scalability. Have you ever observed mineral buildup on your sink faucets and shower heads? That’s scale: mineralization accumulating through time.

What is the cost of flushing a water heater?

A plumber will visit to your home and flush your water heater for between $175 and $275, with an average cost of $225. The real cost will depend on the type of water heater and the plumber’s level of experience.


Is a water heater flush really necessary? Whether you ask fellow homeowners or professional plumbers, you’ll almost certainly get a hearty “yes” in answer.

Flushing your water heater tank offers numerous advantages. This simple maintenance activity will not only keep your hot water flowing, but it will also enhance the energy efficiency of your system. You’ll get higher heating speeds and potentially cheaper energy expenses with an energy-efficient device.

Clovis Plumbing Services provides water heater services to assist with a variety of hot water problems. If you choose to have one of these units in your house, we also specialize in tankless water heaters. Contact us today for more information about our services!

Related Content: Water Heater Draining

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