How Long Do Water Hammer Arrestors Last? A Detailed Guide

How Long Do Water Hammer Arrestors Last?

Water Hammer: You have all heard that loud banging noise in your pipes when you close a faucet or flush a toilet…water hammer. Hydraulic shock — plumbing pipes are divided between “wet” or supply lines and “dry,” which carries away the water that goes down the drain.

Water hammer arrestors are the answer, as they easily diffuse these dangerously high-pressure spikes and thus protect your plumbing. Sure, they are convenient but just how long do these things hold out before requiring replacement?

What Is A Water Hammer Arrestor And How Does It Work?

A water hammer arrester is a basic mechanical gadget that can be quickly set up on the supply line. I enjoyed capturing some great images and videos on how a typical air chamber looks inside, as seen in an example I opened up.

 This pneumatic pressure experience is housed by either rubber or metal that contracts when a water hammer takes place to absorb these hydraulic shockwaves (hence sine wave patterns are not constant), preventing it from going through your lines with ease just like my fantastically flexible forearms:

It helps to prevent loud bangs while at the same time providing protection for pipes and fixtures from damage. When water goes through, arrestors have an internal piston in them which moves down and up with the Darby inside. If a valve is switched off quickly, the water in motion bangs up against this piston containing air – and then the shock has been absorbed. 

As the water pressure is equalized, so the air slowly re-expands. That slowness decreases the pressure wave diminishing it before having an opportunity to propagate into your pipes.

What Factors Determine How Long A Water Hammer Arrestor Will Last?

There are a few key factors that affect the lifespan of a water hammer arrestor:

• Water pressure – Higher water pressure puts more stress on the arrestor’s internal mechanisms and can cause it to wear out faster. Arrestors in homes with 80+ PSI may only last 2-3 years.
• Water quality – Mineral deposits from hard water can build up inside the arrestor, affecting its shock-absorbing capabilities and shortening its lifespan.
• Frequency of water hammer events – The more often the water hammer occurs in the home, the more wear and tear is placed on the arrestor. Frequent events can cause it to fail sooner.
• Location – Arrestors near fixtures prone to causing water hammers (washing machines, dishwashers, etc.) tend to fail quicker than those in other locations.
• Type and quality of arrestor – Less expensive plastic models don’t last as long as brass or stainless steel. Higher-quality arrestors can last 5+ years.

Signs Your Water Hammer Arrestor Needs To Be Replaced

Here are some signs that your arrestor may be failing and it’s time to replace it:

• Loud banging/hammering noises return
• Leaks around the arrestor fittings
• Drop in water pressure
• Fixtures vibrating or shaking from water hammer forces
• Reduced hot water capacity

If your arrestor is more than 2-3 years old, it’s a good idea to be proactive and replace it as general maintenance to prevent water hammer damage. Catching a failing arrestor early is key.

How To Install A New Water Hammer Arrestor

Replacing an arrestor is a straightforward DIY project for most homeowners. Here are the key steps:

• Turn off the main water supply and open the nearby faucet to drain pipes
• Remove the old arrestor from the fittings and discard
• Clean inside pipe fittings with rag
• Apply plumber’s tape to threads of new arrestor
• Screw the new arrestor into the fittings and tighten it with a wrench
• Turn the water back on slowly and check for leaks
• Flush lines and test all fixtures

Be sure the new arrestor matches the pipe size, connection type, and pressure rating of the old one. Most arrestors can be installed vertically or horizontally. Adding a new arrestor costs $10-25 for parts and about 30 minutes of labor. Hiring a plumber usually costs $75-150.

Key Takeaways On Water Hammer Arrestor Lifespan

• Most last 2-8 years depending on water pressure, water quality, usage frequency, and quality of the device
• Higher pressure, hard water, frequent hammer, and plastic models shorten lifespan
• Replacement is needed if loud banging returns or leaks develop
• DIY install is straightforward if the proper arrestor is selected
• Proactive replacement every 5 years is recommended for preventative maintenance

Installing water hammer arrestors is a simple, inexpensive way to save your pipes and sanity by preventing annoying water noises. Be attentive to signs of wear and don’t wait for complete failure. With periodic replacement, these handy devices can offer long-term protection.

FAQs

How can I determine if my arrestor needs replacement?

Listen for the return of loud banging noises when the water is shut off rapidly. Also check for leaks around the arrestor fittings, reduced water pressure, or fixtures shaking from water hammer forces. If your arrestor is over 3 years old, replacement may be needed.

Do arrestors eventually fail and need replacement?

Yes, arrestors have a limited lifespan. The piston and air cushion mechanism wears down over time after repeated water hammer events. The average life expectancy is 2-8 years before failure occurs.

Should I install an arrestor on every plumbing fixture?

Arrestors are most important on fixtures prone to causing water hammers like washing machines, dishwashers, and solenoid valves. They may not be needed at all fixtures but can help protect the system.

Is it difficult to replace an arrestor yourself?

Replacement is usually a simple DIY job taking only 30 minutes. Shut off the water, drain pipes, remove the old arrestor, install a new arrestor with pipe tape, and turn the water back on slowly.

How do I know what type/size arrestor to buy?

Match the pipe size (e.g. 0.5″, 0.75″), connection ends (threaded, soldered), and pressure rating of the existing arrestor. This info should be printed on the arrestor.

Conclusion

In summary, water hammer arrestors are an important and inexpensive plumbing component that helps quiet water noises and prevent pipe damage. Like any mechanical device, arrestors gradually wear out and need replacement every 2-8 years depending on water conditions and usage.

Homeowners can easily install a new arrestor themselves in less than an hour. Periodically replacing aging arrestors is wise preventative maintenance for your plumbing system.