Water hammers are a common problem in many households. They cause loud banging noises in pipes, potentially leading to long-term damage if left unchecked. The sudden pressure surge when water flow is abruptly stopped, particularly in appliances like dishwashers or washing machines, can create shock waves that impact your plumbing system. A water hammer arrestor is a simple yet effective device that can resolve this issue by absorbing the excess pressure and preventing damage.

Key Takeaways:

• Water Hammer Arrestors Prevent Damage and Noise: Water hammer arrestors play a crucial role in protecting your plumbing system from sudden pressure surges. They eliminate loud banging sounds and prevent damage to pipes and fittings.
• Simple Installation in Problem Areas: Installing water hammer arrestors on appliances or faucets that frequently produce water hammers, such as washing machines, dishwashers, and sinks, is straightforward.
• Long-Lasting Solution with Minimal Maintenance: Once installed, water hammer arrestors require little maintenance and provide long-term protection against water pressure issues, making them cost-effective for noisy pipes and plumbing stress.

Understanding Water Hammer

A water hammer occurs when there is a sudden surge of water pressure in a pipe system, often caused when a valve closes quickly. The abrupt stoppage of water flow creates a shockwave that reverberates through the pipes, resulting in a loud banging or thudding sound.

Common Causes:

Water hammer is often caused by appliances or fixtures that suddenly stop water flow. This includes dishwashers, washing machines, or faucets designed to close quickly. In these cases, water flows through the pipes at high velocity, and when the flow is suddenly halted, the energy has nowhere to go, leading to a pressure spike.

Effects of Water Hammer:

• Banging Noise: The most noticeable symptom of a water hammer is the loud noise when the shockwave travels through the pipes.
• Potential Pipe Damage: Constant pressure surges can weaken pipe joints and fittings over time, leading to leaks or burst pipes.
• Leaks: If the water hammer is left unchecked, it can result in small leaks that gradually worsen, causing water damage and increasing repair costs.

What is a Water Hammer Arrestor?

A water hammer arrestor is designed to absorb the shock from pressure surges in a plumbing system. It functions as a buffer, preventing the damaging effects of water hammer by cushioning the pressure spikes that occur when water flow is stopped suddenly.

How it Works:

The water hammer arrestor typically contains either a spring-loaded piston or an air chamber that compresses when a water pressure surge occurs. This compression absorbs the force of the water, preventing it from banging against the pipes and fittings. The arrestor acts as a shock absorber, reducing the strain on the plumbing system.

Common Locations for Installation:

Water hammer arrestors are usually installed near appliances or fixtures that cause water hammers. This includes:

• Dishwashers: Installed on the supply line to prevent the sudden shutoff from creating pressure surges.
• Washing Machines: If the water hammer is placed close to the washing machine’s water valves, it often occurs during the filling cycle.
• Faucets: Installed near quick-closing faucets or other high-pressure fixtures where the problem commonly arises.

Types of Water Hammer Arrestors

Water hammer arrestors come in various types, each suited for different plumbing needs and installation preferences. Choosing the right type depends on the location and the specific issue causing the water hammer. Below are the three main types of water hammer arrestors, each designed to address particular pressure surge issues.

Type of Arrestor	Description	Best Use Cases
In-line Arrestors	It is installed directly within the pipe, allowing continuous pressure regulation along the water line.	It is ideal for larger plumbing systems, homes with high water pressure, or frequent water hammer incidents.
Threaded Arrestors	These arrestors are threaded and easily attached to dishwashers or washing machines.	Perfect for high-pressure appliances, such as dishwashers and washing machines.
Screw-on Arrestors	Designed for easy installation, they can be screwed onto fixtures like faucets or pipes with minimal effort.	Suitable for DIY home plumbing and residential areas with less frequent water hammer.

In-line Arrestors

In-line water hammer arrestors are designed to be installed directly within the pipe, continuously regulating pressure spikes throughout the water system. These are often used in more complex plumbing setups or areas where water hammer occurs frequently.

Benefits:

• Continuous protection throughout the plumbing system
• Ideal for more significant buildings or homes with more frequent water hammer problems
• More durable and effective at handling heavy water flow

Use Case:

In-line arrestors are often used in commercial buildings or large homes where plumbing systems require ongoing water pressure regulation. They are also ideal for locations with high water demand or where multiple appliances operate simultaneously, increasing the chance of pressure surges.

Threaded Arrestors

Threaded water hammer arrestors are equipped with a threaded connection, making them easy to attach directly to appliances that cause water hammers. They are typically used for dishwashers, washing machines, and other high-pressure systems.

Benefits:

• Quick and easy to attach to appliances
• Effectively absorbs shock close to the source of the problem
• Prevents damage to both the appliance and the connected pipes

Use Case:

Threaded arrestors are perfect for high-pressure appliances where water hammer occurs during operation. For example, when a washing machine abruptly stops water flow, installing a threaded arrestor can absorb the resulting pressure and prevent noisy, damaging surges.

Screw-on Arrestors

Screw-on water hammer arrestors are the most accessible type to install, as they screw onto fixtures like faucets or pipes. They are best suited for residential plumbing, where water hammer occurs less frequently or only in specific areas.

Benefits:

• Simple DIY installation, requiring minimal tools
• Effective for small residential applications
• Cost-effective solution for minor water hammer issues

Use Case:

Screw-on arrestors are commonly used in homes for fixtures like faucets or outdoor hoses. They offer a convenient and cost-effective way to manage water hammers without significantly modifying the existing plumbing system.

How to Install a Water Hammer Arrestor

Installing a water hammer arrestor is straightforward and can significantly reduce noise in your plumbing system and prevent long-term damage. Below is a step-by-step guide to help you through the installation process.

Step 1: Identify the Problem Area (Noisy Pipes or Specific Appliances)

The first step in installing a water hammer arrestor is identifying the source of the problem. Typically, water hammer occurs near appliances or fixtures that use water, such as dishwashers, washing machines, or faucets. Listen for the banging noises after the water is shut off, and note which appliance or section of the plumbing system causes the issue.

• Common sources: Dishwashers, washing machines, quick-closing faucets, or toilets
• Location tips: Noisy pipes often indicate the need for a water hammer arrestor closer to that area

Step 2: Turn Off the Water Supply to the Section Needing an Arrestor

Before performing any plumbing work, shutting off the water supply to the section where the arrestor is installed is essential. This ensures no water pressure builds up during installation and prevents leaks or water damage.

• Find the shut-off valve: Look for the valve that controls the water flow to the specific area, appliance, or fixture.
• Turn the valve off: Turn on a faucet and check for water flow to ensure the water is entirely off.

Step 3: Choose the Right Type of Water Hammer Arrestor

Choose the appropriate type of arrestor based on the location and severity of the water hammer. As discussed earlier, there are several types: in-line, threaded, and screw-on arrestors. Each serves different purposes depending on where they are installed and the extent of the issue.

• For appliances (washing machines, dishwashers): Use threaded or screw-on arrestors.
• For general plumbing systems: Consider using in-line arrestors for continuous pressure regulation.

Step 4: Install the Arrestor at the Nearest Accessible Point to the Appliance or Fixture

Locate the nearest accessible point where the arrestor will be installed. This is usually on the supply line, leading to the noisy appliance or fixture causing a water hammer.

• Threaded arrestor: If using a threaded arrestor, attach it directly to the appliance’s water supply connection.
• In-line arrestor: If installing an in-line arrestor, cut into the pipe and place the arrestor inside the line according to the manufacturer’s instructions.

Step 5: Secure the Arrestor in Place with Appropriate Fittings or Attachments

Once the arrestor is in position, secure it using the necessary fittings or attachments. The type of fittings will depend on whether you are installing an in-line or threaded arrestor. Make sure that every connection is firmly fastened to avoid any leaks.

• Tighten connections: Use pipe wrenches or pliers to ensure the connections are snug, but be careful not to overtighten.
• Test for leaks: After securing the arrestor, double-check the connections for any signs of leaks.

Step 6: Turn the Water Back On and Test the System for Noise Reduction

Turn the water supply back on after the arrestor is installed and secured. Slowly open the valve to restore water flow to the affected area. Test the system by running the appliance or fixture causing the water hammer.

• Check for noise: Listen for any remaining water hammer sounds. The arrestor should absorb the pressure surge and eliminate the noise.
• Monitor for leaks: Inspect the area around the arrestor to ensure no water leaks from the fittings or attachments.

When Should You Use a Water Hammer Arrestor?

Water hammer arrestors are highly useful for addressing specific plumbing issues. Here’s when you should consider installing one:

When Experiencing Persistent Banging Noises

If you consistently hear loud banging or thudding noises when you turn off water fixtures, it is likely due to a water hammer. This sound occurs when the water flow stops suddenly, causing pressure surges reverberating through the pipes. A water hammer arrestor can absorb these shockwaves and eliminate the noise, restoring peace to your plumbing system.

• Common situations: This typically happens when using quick-closing appliances like dishwashers, washing machines, or even faucets with high water pressure.

If You Notice Pressure-Related Leaks or Damage to Pipes

Water hammers don’t just create noise; the constant pressure surges can lead to leaks, loose fittings, or even cracked pipes over time. If you see any water damage, especially after hearing pounding noises, installing a water hammer arrestor will help prevent future deterioration and expensive repairs.

• Indicators to watch for: Small leaks around joints, damp patches near pipes, or visible pipe damage can indicate harmful water pressure in your plumbing system.

For Preventing Long-Term Damage in High-Pressure Water Systems

The impact of the water hammer is more pronounced in systems with consistently high water pressure. Over time, repeated pressure surges can weaken plumbing infrastructure. A water hammer arrestor is a preventive measure that absorbs these pressure fluctuations and keeps pipes in better condition.

• Proactive approach: Even if you don’t hear banging noises, high-pressure systems can benefit from arrestors to avoid gradual damage.

Installing During Home Renovation or Plumbing Updates to Future-Proof the System

If you are renovating your home or updating your plumbing system, installing water hammer arrestors proactively is a good idea. By incorporating them during the renovation, you will future-proof your home against potential water hammer issues that may arise as you upgrade or modify your plumbing system.

• Strategic locations: Install them near appliances or sections where high water flow is expected, such as kitchens or laundry areas.

Maintaining Water Hammer Arrestors

Water hammer arrestors are generally low-maintenance devices, but regular monitoring can ensure they continue functioning effectively for years.

Lifespan of Arrestors

Water hammer arrestors are built to last, often providing long-term relief from water hammer issues. However, like any plumbing device, they can wear out over time. If the banging noises return or if pressure surges start happening again, it may be time to check or replace the arrestor.

• Typical lifespan: Arrestors can last over a decade, but their longevity depends on water pressure levels and frequency of use.

Monitoring for Pressure Issues in Plumbing

Look for any pressure problems or water pounding in your plumbing system. Listen for sounds, check for leaks in pipe joints, and note odd water flow patterns. Early detection of pressure problems allows you to address them before they cause significant damage.

• Tip: Make monitoring your water pressure a part of routine home maintenance, especially if you have older pipes or fixtures.

Cleaning and Replacing Old or Damaged Arrestors

Over time, water hammer arrestors may accumulate debris or mineral deposits that reduce their effectiveness. While they don’t require frequent cleaning, you should check them periodically, especially if water hammer noises return. If the arrestor is damaged or no longer effectively absorbs shock, it should be replaced to ensure your plumbing system remains protected.

• Cleaning tip: Follow manufacturer guidelines regarding whether the arrestor can be cleaned or should be replaced entirely.
• Replacement: If the arrestor is over ten years old or showing signs of failure, consider installing a new one.

FAQs

What is the primary purpose of a water hammer arrestor?

A water hammer arrestor absorbs the shock and pressure from the water hammer, preventing pipe damage and reducing noise caused by sudden water pressure changes.

Do I need a plumber to install a water hammer arrestor?

While homeowners can often do installation with basic plumbing skills, it’s advisable to consult a plumber for more complex systems or if you’re unfamiliar with plumbing work.

Where should a water hammer arrestor be installed?

It should be installed close to the appliance or fixture causing the water hammer, such as dishwashers, washing machines, or faucets.

How long does a water hammer arrestor last?

Water hammer arrestors are typically long-lasting, often lasting over a decade, but their lifespan depends on water pressure levels and usage. Regular checks are recommended.

Can a water hammer arrestor fix all types of water noise?

A water hammer arrestor is effective against noise caused by a water hammer but may not address other plumbing noises, such as those caused by loose pipes or air in the lines.

Conclusion

Water hammer arrestors are vital for maintaining a quiet, damage-free plumbing system. Whether you are dealing with persistent banging noises, pressure-related leaks, or simply looking to protect your home’s pipes from long-term stress, installing a water hammer arrestor can provide an effective solution. By absorbing the pressure surges caused by sudden water stoppages, these devices prevent noise and protect your plumbing system from potential damage that can lead to costly repairs.

Incorporating water hammer arrestors during renovations or upgrades is an intelligent, preventive measure that ensures your plumbing system remains in optimal condition. Because of their low maintenance needs and extended lifespan, water hammer arrestors are an affordable investment in the long-term viability of your house’s plumbing system.

Regularly monitoring your plumbing for signs of water hammer and maintaining your arrestors as needed can ensure a quieter and more efficient water system, providing peace of mind and safeguarding your home from potential plumbing disasters.