Illustration: Water Hammer in Pipes
Learn about water hammer and its prevention.

Water hammer, or hydraulic shock, is a rapid rise in pressure that occurs when there is a sudden change in fluid velocity after the sudden opening or closing of a faucet or a sudden pump start-up or stoppage.

This can cause major problems like backflow and an increase in flow rate and banging water pipes.

The force of the water hammer is comparable to the force of an explosion. The shock wave falls into the pipeline until it hits a curve (a pipe elbow or a larger pipe, for example) and flows back instantly to the initial point of impact.

How to Prevent Water Hammer

Unless your home’s plumbing system is very old, you probably already have one solution in place: air chambers.

Air chambers are short vertical pipes installed right behind a valve. Because this piece of pipe is installed higher than the valve, it fills with air instead of water. The air acts as a shock absorber when the flow of water stops suddenly.

On the other hand, water hammer can occur even when an air chamber has been installed. That happens when water bubbles up into the chamber over time.

Before calling a plumber, try fixing it yourself by following these simple steps:

  • Shut off your main water valve
  • Open faucets at the highest and lowest points in your home.
  • As the remaining water drains from your plumbing system, the air chambers will automatically refill with air.
  • Reopen your main water valve and check the noisy faucet or appliance to see if the problem is fixed.

If your plumbing system is lacking air chambers, you might want to have them installed, even if water hammer hasn’t already hammered away at your nerves. You could also have devices called water hammer arrestors installed in the same place.

Check Your Water Pressure

Even with air chambers or water hammer arrestors, water hammer can persist when the water pressure is too high. You can find out quickly enough by purchasing a water pressure gauge. Screw it onto your hose bib and fully open the faucet while all the other faucets and fixtures in your home are closed. Safe water pressure can range anywhere from 50 to 80 psi. If yours is higher, you have yet another reason to contact Anthony’s Plumbing, Heating & Air Conditioning.

For water hammer or any other home comfort need related to your plumbing and HVAC systems, we have the people, experience, and resources to do the job correctly – the first time.

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