Easy Water Hammer Fix

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How to eliminate water hammer in home water heating systems. What causes the problems, symptoms and how to fix it.


Probably you have experienced with your water heating and plumbing system a loud noise - banging or thumping noise when you turn off hot or cold water tap. This problem is known as water hammer and it can affect both new and old houses.

What is a water hammer?

This problem is the result of the vibration in the plumbing, either copper, CPVC or steel, and it develops when you close the tap fast which stops the flowing water abruptly. Either you have a single lever faucet or faucet with the solenoid valve, this problem might happen. Repetitive loud bang noise happens because the high-pressure shock wave travels through the plumbing system and banging against the walls and from one to other end.

Problems and symptoms

  • Loud banging or thumping noise.

  • Collapsed flue tube on gas heaters.

  • Deformation on the top of the heater.

  • Expansion in the tank shell.

  • Damages to piping, TPR valve, water meter, pipe joints.
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Troubleshooting and how to stop a water hammer

The fix is simple. Next time turn the tap off slowly and there will be no loud noise coming from the plumbing, as the water inside the system will slow down gradually.

water hammer arrestorIf the above suggestion does not solve the problem, you might need something which is called an arrestor, also called an air cushion or air chambers. This device is filled with the air which is connected to the plumbing so the vibrations will dissipate into this cushion of air, protecting the system from high-pressure shocks. If the arrestor fails, it might be clogged with the accumulated scale and will need proper cleaning.

There are some suggestions from the manufacturers, such as Bradford White, that problem can be solved by installing the expansion tanks and pressure relief valves with the setting at 25-50 pounds less than the TPR valve on the heater.

Also, I have read few reviews where it was said that there is nothing you can do about water hammer. That is not true, you have to do something, otherwise you might have problems, as described in the above section. Remember, this problem is associated with the high water pressure which has to be reduced, either by installing the pressure reduced valves or air chambers - arrestors.

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