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How to Clean a Water Heater: and How to Dissolve Sediment

Cleaning your water heater is crucial if you want it to preserve its lifespan.

Knowing how to clean a water heater is crucial to the longevity of your appliance. With the proper maintenance program, it could last 10 or 15 years. Skip water heater cleaning and your water heater will probably break down.

We show you how to clean a hot water heater, including tips for cleaning gas, electric, and tankless models.

Key Takeaways

  • Flush your water heater at least once a year to remove sediment and maintain its longevity.
  • Turn off the power and water supply before draining the tank, and let the water cool for safety.
  • Use white vinegar to dissolve stubborn sediment and clean the inside of the tank.
  • Regularly clean the exterior of your water heater, including pipes and the base, to prevent dust build-up and malfunctions.

How Often to Clean a Water Heater?

It depends on your area, but you should flush your water heater at least once a year. Check with the Environmental Protection Agency (EPA) for the water quality in your region.

If you have a water softener, you might not need to flush the system as often. The sediment has been removed before it gets inside your water heater.

How to Flush an Electric Water Heater

It’s “flush the water heater” day (we know, it doesn’t get any more exciting). But before we get started, you need the right tools and materials.

What You’ll Need

  • Hose.
  • Towels.
  • Wet/dry vacuum cleaner.

1. Get the Tank Ready for Flushing

You will need to isolate the power at the breaker board. You will find it in a cupboard, in the basement, or attached garage. Turn the water off at the tap on top of the heater. This stops the supply line feeding the tank when you empty it.

2. Run the Hot Water Faucets

Open the nearest hot water faucets to the water tank. This helps drain the tank and removes the chances of a vacuum forming inside the boiler.

3. Attach a Hose

Connect a hose length to the drain tap at the base of the water heater. If you have a floor drain, lay the hose over the drain hole. If not, you need to lay the other end of the hose outside.

4. Open the Drain Valve

Lift the lever on the drain valve to empty the water from the tank. You may notice the sediment rushing from inside the heater. This indicates just how dirty your water heater has become.

In some extreme cases, sediment build-up may restrict the tank from draining. Shut off the drain valve and attach a wet/dry vacuum cleaner to suck out the sediment.

You’ll need to try an alternative method if it doesn’t clear the blockage. We’ll come on to that later.

Word Of Caution

It’s safer to let the water cool for an hour or two before draining the tank.

5. Turn the Water Back On

Open the water supply and let the water push the last remnants of sediment out of the tank. Keep the hose attached for a few minutes while the tank drains. Finally, turn the cold water supply off again.

6. Shut Off the Drain Valve

Shut off the drain valve and disconnect the hose before switching on the cold water. Turn on the water again and wait while the tank fills.

7. Close the Faucets

You may notice discolored water running from your faucets as the tank drains. Leave them open for a few minutes until it starts to run clear. Then turn them off.

8. Prepare the Water Heater for Use

Switch the heater back on at the breaker board and reset the thermostat to the desired heat level. Switch the water heater back on and wait a few hours while the heater elements do their work.

How to Clean the Outside of a Water Heater

Cleaning the inside of the water tank is one thing, but you should also take care of the exterior of your water tank. Dust and grime accumulate and could cause a heater malfunction.

What You’ll Need

  • Vacuum cleaner (with hose attachment).
  • Clean cloth.
  • Warm soapy water.
  • Dry towel.

1. Vacuum the Exterior

Attach the brush hose to your vacuum cleaner and run it over the surface of the boiler to remove any dust layers. Focus on pipes and the base of the heater, as well as around the back where dust accumulates.

This Hoover MaxLife model is powerful and has the attachments needed to reach awkward places on your boiler.

2. Wipe the Heater Down

Dip a cloth in warm soapy water and wring it out. Rub down the tank’s surface to remove stubborn dirt. Again, focus on the pipes and areas around the base and back of the boiler.

3. Dry the Water Heater

Use the towel to wipe the exterior dry. This is important because leaving water on the surface could cause the heater to rust.

How to Clean a Water Heater With Vinegar

When you’ve flushed the tank and sediment is still blocking the drain valve, you will need something stronger to dissolve the mineral deposits. White vinegar is an excellent treatment to descale your water heater.

What You’ll Need

  • White vinegar.
  • Wrench.
  • Funnel.

1. Drain the Tank

Follow steps one to four of the “How to Flush an Electric Water Heater” section.

2. Remove the Anode Rod

Check your manual for specific instructions to remove the anode rod. They generally unbolt with an adjustable wrench.

3. Add the Vinegar

With the rod removed, there should be a hole in the tank. Place the funnel into the hole and pour four gallons of white vinegar into the tank. This Heinz Cleaning Vinegar is an excellent product to use.

4. Reattach the Anode Rod

Bolt the anode rod back in place with the wrench and switch on the water supply. This agitates the vinegar, mixing it with the water as the tank fills. Leave the vinegar to sit inside the tank for 24 hours to dissolve the sediment.

Finally, follow steps one to eight to drain the vinegar from the tank and flush it through. This ensures that the vinegar and dissolved sediment drains away, leaving you with a clean hot water heater and tank.

How to Dissolve Sediment in a Water Heater

Dissolving sediment is an effective way to delime your water heater. Aside from vinegar, what other methods exist to descale your water heater?

Descaling Agents

You can purchase descaling chemicals from your hardware store or online. They are powerful and very effective at dissolving limescale. This Essential Values Descaling Agent is natural and safe for the environment.

You can use it in most appliances, from your kettle to your water heater. You need to drain the tank the same way as using vinegar once the sediment dissolves.

Install a Water Softener

Installing a water softener may seem like an expensive way to solve the problem of scaling appliances, but it is effective. This Whirlpool Pro Series Water Softener is an excellent example of what is available to you.

It filters sediment and chlorine, reduces water odors, and it even cleans its own filter. And best of all, it’s engineered and assembled in the USA.

Tips for Cleaning Different Types of Water Heaters

Smiling technician servicing a hot-water heater

There are three types of water heater: gas, electric, and tankless. But what are the tips for effectively cleaning them to preserve their longevity? Let’s take a look.

Electric Water Heater

  • Turn the power off at the breaker board rather than at the switch on the unit. The last thing you want is for the heater to start up mid-drain.
  • Wear rubber gloves to prevent electrical shocks.
  • Switch off the heater a couple of hours before draining. It’s easier and safer to drain the heater when the water has cooled.
  • With the tank empty, remove the elements to check for corrosion.

Gas Water Heater

  • When vacuuming the exterior, always pay attention to the draft hood. This is where dust build-up could have a fatal impact on your water heater.
  • Ensure that the gas supply is shut off to prevent inhaling poisonous fumes.
  • Check the gas line for corrosion. A damaged gas line could lead to gas leaks further down the line.
  • While draining the tank, check the elements and thermostat are in working order.

Tankless Water Heater

  • Shut off the yellow, red, and blue water taps at the base of the heater.
  • Drain the water from the pipes via the purge pipes. Take care when draining the hot water.
  • Use washing machine water pipes rather than a hose. You get a better attachment and can drain the water into a bucket.
  • Always disconnect the power at the main breaker board. If you have a tankless gas heater, shut the gas off as well.

Water Heater Flush Costs

Suppose you have neither the will nor inclination to flush your water heater yourself. What are the costs of employing a plumber to do the work? Let’s take a look.

You can expect to pay between $80 and $100 for a pro to flush your water heater. Some plumbers have a minimum call-out fee, so they may hike the price further to cover their time, travel, and other sundry costs.


How Long Do You Flush a Water Heater?

You should flush your water heater annually, although if you have a water softener, you may stretch this to every three years.

How Do I Know If There is Sediment In My Water Heater?

If your tank starts making popping noises, there is a strong chance of sediment coating the bottom of your tank.

How Do I Clean Sludge From the Bottom of My Water Tank?

The easiest way to remove sludge from the tank’s base is to flush it through by draining the tank. This removes the contaminated water and washes the tank clean. Then you will need to refill the tank with fresh water.

Clean Water Heater Final Say

Whichever type of water heater you own, we cannot overemphasize the importance of regular maintenance. It saves you money and keeps your hot water flowing. Plus, you get the satisfaction of knowing you did it yourself.

That’s got to be a win-win as a homeowner.

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About the Author

Mark Weir

Mark spent 24 years working in real estate, so he knows his way around a home. He also worked with contractors and experts, advising them on issues of planning, investments, and renovations. Mark is no stranger to hands-on experience, having renovated his own home and many properties for resale. He likes nothing better than seeing a project through to completion.