Where Should I Install a Water Hammer Arrestor?

Upgraded Home Team
by Upgraded Home Team

A water hammer occurs when there is a sudden increase in a pipe’s water pressure when the water is suddenly forced to stop. This occurrence often creates a loud banging sound. Water hammers do more than create an annoying level of noise. These abrupt changes can severely damage a piping system.

Therefore, one should place a water hammer arrestor as close as possible to the last fixture on a water line. If the noisy line is greater than 20 ft., put 2 arrestors.

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What Causes a Water Hammer?

A water hammer is the result of water pressure suddenly building from abruptly closing a valve, such as turning a faucet off. This is because the water is rushing from the higher-pressure pipe into your low-pressure sink.

Water Hammer Damage

There are several ways a water hammer can cause damage:

  • Leaks: The high pressure that occurs during a water hammer can damage joints and fittings. These leaks may be small at first, but they can increase substantially over time.
  • Collapse or Rupture: The surge of pressure during a water hammer is sometimes high enough to cause the pipes to collapse. The damage to pipelines caused by recurring water hammers may also lead to ruptured pipes.
  • Injuries: Leaks, ruptures, or collapses caused by water hammers may lead to injuries due to slips, falls, or even electrocution.
  • Property Damage: Leaks, collapses, or ruptures can also cause damage to surrounding property such as floors or walls. The cost to repair this damage could be considerable.

Preventing a Water Hammer

There are some simple things you can do that may prevent a water hammer without any repairs:

  • Turn off the water faucet more slowly; this allows the water to slow down before stopping.
  • Tighten any loose fittings on your pipes; this could eliminate your problem.
  • Check your water pressure; get a pressure gauge and check the water pressure. The water may be entering your house at too high of a pressure. In this case, you may need to attach a water pressure regulator.

How Does a Water Hammer Arrestor Work?

A water hammer arrestor is simply a t-fitting in your pipe that branches into an expandable diaphragm. Imagine a balloon inside a solid pipe. As the water pressure builds, the balloon expands; when the pressure drops, it shrinks.

How Many Arrestors Do I Need?

You need as many arrestors as you have problem water lines. You may have multiple distinct water lines and potentially narrow pipes, increasing water velocity.

You may install 1 or 2 arrestors near a problem fixture and find another fixture causing a problem. If so, install another arrestor near the new problem fixture.

How Do I Decide Where to Place an Arrestor?

Place the arrestor near the last fixture on a water line. If you are installing one, you probably have heard banging from your pipes. That probably indicates which fixture is the problem.

If your washing machine in the garage is causing the noise, it’s probably near the end of its water line. This would be the place to install the arrestor.

How to Install a Water Hammer Arrestor?

Installing a water hammer arrestor is not difficult. Just follow these steps.

If you have never used a torch before, be careful. If you need to purchase one, there are multiple options:

  • Find the pipe you are installing an arrestor on and measure its diameter.
  • Purchase an arrestor with a t-fitting that matches the diameter of your pipe.
  • Turn the water supply to your house off.
  • Use a pipe cutter and remove a section of the pipe long enough to insert the t-fitting.
  • Clean the exposed ends of the pipe with sandpaper and wipe flux onto both ends as well as the t-fitting.
  • Insert the t-fitting and solder the fitting in place with a torch.
  • Cover the arrestor’s threads with Teflon tape to prevent leaking and twist it in snugly with an adjustable wrench.
  • Turn the water supply on and test for water hammer and leaking.

Other Ways to Reduce the Sound of a Water Hammer

Much of the sound created by a water hammer is the jostling of your pipes. The sound is created by the increase in pressure. Reduce this pressure by using clips to hold your pipes tightly in place.

Covering pipes in insulation can reduce the sound of pressure waves and from jostling against the walls of your home.

If a metal pipe is shaking along its length making a snap clamp out of pvc may deaden its vibration.

Repairing a Leaking Pipe

If you find a pipe developed a leak while working, you could call a plumber. However, it may be possible to fix it yourself.

If the pipe can be disconnected, first, slip a flexible coupling over it. Then, tighten it with hose clamps.

If you are confident using a torch to solder, many leaks can be solved by filling them with solder. Another option is cutting a thicker piece of pipe and using it to replace the leaking section. Be sure to leave overlap with the surrounding pipes.

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Related Questions

How to Detect Water Damage in Your House

There are several things to look out for if you suspect water damage in your home:

  • Look for loose or discolored flooring. Also, check for signs of mold under your flooring. If you see any of these signs, water may be leaking under your flooring.
  • Examine your walls for any sign of peeling, swelling, or even soft spots. You may also see visible mold. If you see any of this, water may be leaking behind your walls.
  • Check your house for musty odors. Water leaks may be causing damage leading to mold in places that are not visible.
How to Prevent Water Damage

With proper care, you can prevent water damage. You can take some steps that will save you money by stopping water damage before it starts:

  • Inspect the caulking in your shower and tub. If there are any cracks, they can be re-caulked at little cost. Otherwise, they may leak into your floors and walls, causing damage.
  • Check all faucets and any hose attached to appliances to make sure they are not loose. Tighten any that are loose, because loose fittings can leak, causing water damage.
  • Examine your water heater. If you see signs of rust, it may be leaking, which could damage your floor.
Why Do My Pipes Click When I Run Hot Water?

This is often caused by a CPVC pipe expanding inside a small area. This is solved by giving it more room to expand.

What Causes a Loud Banging from the Water Heater with No Water Running?

This can be caused by steam escaping sediment building up in the water heater. This is solved by flushing the debris out.

Upgraded Home Team
Upgraded Home Team

We are a team of passionate homeowners, home improvement pros, and DIY enthusiasts who enjoy sharing home improvement, housekeeping, decorating, and more with other homeowners! Whether you're looking for a step-by-step guide on fixing an appliance or the cost of installing a fence, we've here to help.

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