Have you ever heard a loud banging sound in your pipes after shutting off a faucet or appliance? That sudden thud is called a water hammer, and it’s more than just annoying it can cause serious damage to your plumbing over time. So, what does a water hammer arrestor do? It’s a small yet powerful device that protects your plumbing system from pressure spikes that create those loud noises. But there’s more to this tool than just noise control.
In this blog, we’ll break down exactly what a water hammer arrestor does, how it works, why it’s necessary, and how to tell if your home needs one. We’ll also cover how it ties in with related components like a hammer arrester valve, air hammer arrestor, and more, helping you understand the full picture behind managing water pressure in your pipes.
Understanding Water Hammer and the Need for Arrestors
When water is flowing through your pipes and you suddenly shut off a valve whether from a dishwasher, washing machine, or faucet the water, still under high pressure, has nowhere to go. This force slams into the closed valve, causing pipes to vibrate and create a loud banging sound. This is what’s known as a water hammer.
Over time, this pressure surge can cause pipe joints to weaken, valves to fail, and even cause leaks behind walls. That’s where a water hammer arrestor comes into play. It absorbs the shock of the sudden stop in water flow and prevents the pipe from reacting violently.
How Does a Water Hammer Arrestor Work?
To truly understand what does a water hammer arrestor do, it’s important to grasp the inner workings of this small but mighty device. A water hammer arrestor contains either a cushion of air or a spring-loaded piston inside a sealed chamber. When the valve shuts and pressure builds, the piston or air chamber compresses and absorbs the energy, stopping the bang in its tracks.
Whether you’re installing a hammer arrester valve in a laundry room or an air hammer arrestor near a water heater, the concept remains the same. It provides a buffer that stops pressure from harming your pipes and appliances.
Where Are Water Hammer Arrestors Installed?
Most plumbing hammer arrestors are installed near appliances or fixtures that shut water off quickly. Common places include:
-
Behind the washing machine
-
Under kitchen sinks with automatic shutoff faucets
-
Near dishwashers
-
Beside toilets that refill rapidly
Professional plumbers usually place them in accessible areas where pressure buildup is most likely to occur.
Signs You May Need a Water Hammer Arrestor
Here’s how to tell if your home might benefit from one:
-
You hear loud thumping or banging when you shut off water.
-
Appliances like dishwashers or washing machines cause vibrations in pipes.
-
You’ve recently remodeled your plumbing system, adding modern valves that shut off quickly.
-
Pipes are aging or already showing signs of leaks or cracks.
Ignoring the problem won’t make it go away. Over time, unchecked water hammer can lead to costly repairs or even plumbing failure.
What Happens If You Don’t Use a Water Hammer Arrestor?
Without a plumbing hammer arrestor, your pipes and fixtures absorb every shock wave caused by sudden water stoppage. Over time, this can lead to:
-
Broken pipe joints
-
Damaged water valves
-
Leaky plumbing systems
-
Increased utility bills from inefficient plumbing
-
Mold and mildew due to hidden leaks
If you’re hearing persistent knocking sounds, it’s time to investigate further and possibly install an air hammer arrestor or hammer arrester valve to correct the issue.
Are Water Hammer Arrestors Required by Code?
In many newer homes and renovations, building codes require water hammer arrestors to be installed, especially for washing machines and dishwashers. These high-pressure appliances are more likely to create water hammer problems. Even if your area doesn’t mandate it, installing one is a smart, preventative decision.
How Long Does a Water Hammer Arrestor Last?
A typical water hammer arrestor can last anywhere from 10 to 20 years depending on the quality of the material, water pressure levels, and frequency of use. However, if you’re in an area with hard water or high pressure, they might need to be inspected more often.
Now, speaking of lifespan—it’s important to understand that, just like how long does a septic system last, regular maintenance and proper installation are the keys to long-lasting plumbing components. When your plumbing hammer arrestor begins to fail, you might start hearing those banging noises again—so don’t ignore the signs.
Choosing the Right Arrestor: Air vs. Piston Type
There are two common types of water hammer arrestors: those that use a sealed air chamber and those with a spring-loaded piston. Air chamber types are cheaper but may lose effectiveness over time if water replaces the air. Piston-style arrestors are longer-lasting and more reliable, making them a better choice for high-use areas.
If you’re not sure which type is best for your home, it’s wise to consult a licensed plumber who understands your system layout.
How to Maintain Your Water Hammer Arrestor
Luckily, water hammer arrestors are low-maintenance. Once installed correctly, they generally don’t require much attention. But like any plumbing device, they can eventually wear out. Pay attention to signs like the return of banging pipes or visible corrosion. At that point, it’s time to have the device checked or replaced.
Should You Install One Yourself or Call a Pro?
While some handy homeowners might feel comfortable installing a hammer arrester valve, it’s not always a DIY-friendly job. Proper placement, sizing, and sealing are critical to getting long-term benefits. Incorrect installation can cause leaks or reduce effectiveness. For the best results, hire a licensed plumber to install the device properly.
And if you’re tackling more than one plumbing issue like needing a new toilet installed or valves replaced—it’s worth bringing in the pros.
Let Derks Plumbing Handle It For You
If you’re dealing with noisy pipes, unsure about your plumbing pressure, or simply want peace of mind, Derks Plumbing can help. Our professional plumbing team understands how to install water hammer arrestors efficiently and securely. We also offer expert solutions for toilet repair, water line installation, and valve replacements all under one roof.
Don’t let a small thud turn into a big problem. Visit Derks Plumbing to explore our full range of services.
FAQs: What Does a Water Hammer Arrestor Do ?
Q1: What causes water hammer in pipes?
Water hammer is caused by the sudden stoppage of flowing water, creating shock waves in the plumbing system.
Q2: Can I ignore water hammer sounds?
Ignoring them can lead to long-term damage to your plumbing, including burst pipes and leaky joints.
Q3: How long do water hammer arrestors last?
Most last 10–20 years depending on the type and water pressure in your home.
Q4: Can I install a water hammer arrestor myself?
Some are easy to install, but professional help is recommended for best results and code compliance.
Q5: Do water hammer arrestors need maintenance?
Not usually, but they should be checked periodically for signs of wear or failure.
