How to Remove Sediments from a Water Heater and Boost Performance

Learn how to remove sediments and mineral deposits from electric and gas water heaters. Find out the cause, symptoms, and how to troubleshoot to prevent the element failure and increase performance and efficiency. Check out the best way to avoid the sediment buildup problem.

Sediments in a water heater and what you can do about it

  1. What are the sediments
  2. Common problems due to sediment build-up and solutions
  3. How to remove sediments and limescale from a water heater
  4. How to prevent and reduce mineral deposits
  5. Highlights of the problems caused by the sediment buildup
  6. Self-cleaning systems as a solution

What are the sediments

Sediments are mineral deposits found in any water heater storage tank, whether it is a newer model or an old one. Mineral deposits are usually found at the bottom of the tank, on the heater's elements, and especially when water is heated. The amount of deposits depends on the water type, its hardness, the presence and efficiency of the self-cleaning system.

Sediments are found in water in solid shapes, like sand or particles coming from the well or municipality system and not dissolved. Even pieces of the limescale buildup and rust.

Rust deposits, for example, are the result of the aggressive water action when the tank starts corroding due to lack or failed rust protective elements like anode rod or metal tank lining.

Common problems due to sediment build-up and solutions

The sediments in the plumbing and water heaters will eventually cover the elements such as electric heating elements, gas burner, also clog the valves, faucets or reduce the water flow. All these problems can lead to lower efficiency and performance, reduced power output, even shorter element life; and are a good sign that the water heater needs flushing and draining.

In such cases, users will mostly complain that there is "no hot water," "not enough hot water," "water temperature fluctuates," there is "popping, rumbling or sizzling noise," and so on.

For example, popping or sizzling noise comes when water is trapped under the limescale, next to the heating elements.

Even if the noise disappears due to the change in water scale structure, that doesn't mean that tank flushing is not necessary; be aware that tank or heating elements can fail.

Lime buildup increases when the water is heated; with increased temperature and water hardness, higher usage, and increased heating surface. Deliming is a necessary operation that has to be included in the regular maintenance and service.

Sometimes, the problem with sediments is significant, making the tank hard or not even worth cleaning, so buying a new electric or gas appliance is the only option.

How to remove sediments and limescale from a water heater

Drain valve on a water heaterUse a drain valve to flush water with sediments
(photo: amazon)

If your water heater is not performing as it should, or you hear the unusual noise inside the heater, as mentioned above, you have to act accordingly. Deposits are often loose, which makes them easy to remove. If you wait for too long, the water scale can harden and make it tougher to remove.

One of the solutions to get rid of the sediments from the tank-type heater, including the limescale, is to dissolve the residue with the delimer solution, like phosphoric acid or vinegar and flush it out. Vinegar, for example, can be poured in through the opening once you remove the anode rod for checking and replacing. Let the vinegar sits for several hours to dissolve the limescale, and then flush it out.

Manually scraping some elements is another fix, but it is time-consuming, and it is harder to reach some parts and clean them in full.

Decreasing the hot water temperature can slow the formation of limescale while installing the water softener can significantly reduce the hardness of water, and the anode rod can be affected.

YouTube video: How to clean flush and drain sediments from a water heater


Due to all these reasons above, prevention is the way to go.

The preventive and regular maintenance includes flushing and draining operation. The procedure is described here, in detail, and it looks like this - in short:

  • Turn the electricity to the water heater OFF (especially if the unit is electrical).
  • If it is a gas-type model, turn the gas valve OFF or set it to "Pilot."
  • Turn the cold water OFF.
  • Attach one side of the garden hose to the drain valve located at the bottom of the unit, and put the other end of the hose into the nearby safe drain location, such as the floor drain or sump pump pit.
  • Open up the hot water tap to prevent vacuum buildup inside the tank while draining.
  • Open up the drain valve to drain the water from the water heater.
  • If there are still sediments inside the tank (drained water is not clear), half-fill the tank with cold water and drain again. This way, cold water will loosen up the rest of the sediments, and the water stream will flush them out.

Tools that you need to do the job:

  • Garden hose
  • Socket wrench
  • Bucket
  • Teflon tape
  • Brush for scrubbing

Note: In the case of the electric water heaters, if the water is emptied from the tank and if the power is turned ON, the heating element is exposed to the air, which will eventually burn out the element.

So, turn the power OFF. Also, it is important to have the tank full of water, bleed out all the air from the tank, using the TPR valve and hot water tap. When the hot water tap is open, water should be running continuously.

Highlights of the problems caused by the sediment buildup

  • Not enough hot water deposits form the insulating layer between the heating elements and water, decreasing the contact surface and heat transfer.
  • Noisy operation - sizzling and hissing are characteristic of electric water heaters, while gas and oil-fired units may rumble and pound.
  • Longer heating time.
  • Shortened heater's life.
  • Reduced efficiency.
  • High operating costs are the result of the increased energy consumption.
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How some water heater manufacturers fix the sediment build-up problem

Below are examples, how some big water heater manufacturers in North America are fixing problems when the sediment and limescale deposits occur in the tank.

DynaClean is the patented automatic cleaning system from the AO Smith water heating company. Thanks to the specifically designed dip tube that creates cold water turbulence in the tank, sediments and lime buildup accumulated from the hard water are significantly reduced.

Hydrojet Total Performance System is the patented system from Bradford White that fights mineral buildup in the tank while extending the first hour delivery.

Everkleen Self-Cleaning System is Rheem's patented technology that uses the high-pressure spiraling stream.

All these self-cleaning systems are helping operating efficiency and extending the tank life, maintain high energy efficiency, maximizing the output while saving energy and money.

Note: In most cases, the manufacturer's warranty does not apply if there is a heater failure due to rust, scale and lime buildup, and deposits.


If you are the owner of a tank-type water heater, you should not ignore the sediment buildup, even at its early stage. Sediment buildup is not harmful as long as the water is soft, but if water is hard and neglected for some time, deposits can make the system inefficient, valves clogged, metal tank corroded, and eventually leaky.

While there are some ideas on breaking the buildup and removing the deposits from the tank, the easiest and safest way is to maintain (drain and flush) the unit regularly because prevention is the key.

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