Why You Should Descale Your Water Heater


Why You Should Descale Your Water Heater

May 15, 2018

It’s important to descale your system at least every two years. When you heat water, you leave dissolved solids behind. This creates a build-up over time in your water heater that can lead to lost efficiency and flow. It can even cause your water heater to overheat and then you could have to call in an emergency plumber for potentially costly repairs.

What You’ll Need

A System Descaler: This consists of a pump, a bucket, and some hoses.

Descaling Solution: A food-safe, biodegradable cleaning solution.

The Proper Valves: You must have the proper valves connected to your water heater in order to complete this process. If you do not have valves installed on your tankless water heater, be sure to give Best Plumbing or your local plumber a call.


  1. Turn the valves off. This will ensure that no water spills out of your heater.
  2. Remove the hose threads from the second hot and cold water ports.
  3. Take the hose from your system descaler and attach it to the hot valve. Place the other end of this hose in your bucket.
  4. Attach the hose that is connected to your system decaler pump to the cold valve.
  5. Turn the cold water back on.
  6. Turn the hot water on and let water flow into the bucket. Let enough water flow into the bucket to submerge the pump, then turn the water off.
  7. Add the solution to the bucket.
  8. Make sure that all of the hoses are connected on last time and turn on the secondary tap. You can turn the gas off at this point so you are not heating the water as it goes  through the system. You’re ready to start the descaling!
  9. Plug in and turn on your pump. Let it run for about an hour.
  10. Turn off the pump.
  11. Turn the inlet and outlet valves off and remove the hoses.
  12. Turn the hot water valve back on and let the water that is left run out. If your water heater is indoors be sure to place a bucket beneath the flow of water.
  13. On the underside of your tankless water heater you should find a small screen that can be unscrewed. Pull this out and check that it is now clean.
  14. Rinse off the screen in the leftover solution and clean off any remaining debris. Now that everything is clean, it’s time to run fresh, clean water back through the heat exchanger to remove any left over solution in the system. First, reattach your hose to
  15. the hot side of the system.
  16. Leave the hot side isolation valve off.
  17. Turn on the cold water to pressurize the system.
  18. Turn the hot water hose port on, and then turn the gas back on. Let water run through the system until it’s warm.
  19. Turn the valve off and unscrew your hose.
  20. Replace the cover on the hot water valve and turn the isolation valve back on.
  21. Do one last check that your gas is on, both hose ports are in the off position, and both isolation valves are in the on position.

If you are worried about completing these steps on your own, do not have the proper tools, or have any other plumbing concerns, contact Best Plumbing today. We are happy to assist you however we can.

For more useful plumbing tips, check out our blog and Youtube channel!

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