Do I Need Water Hammer Arrestor For Washing Machine? (And Dishwasher)

Are you tired of loud banging noises during the water supply cycle?

A water hammer can be frustrating when water flow is abruptly stopped, causing pressure surges and loud noises in your plumbing system. But do you need a water hammer arrestor for your washing machine and dishwasher?

Yes, a water hammer arrestor is recommended for your washing machine and dishwasher to mitigate the water hammer and protect your plumbing system from potential damage.

Discover the benefits and functionality of water hammer arrestors. Read on to learn more about this valuable solution and bid farewell to disruptive water hammer noises.

Water Hammer Arrestor

Water hammer arrestors are devices installed in appliances with fast-closing valves. The arrestors absorb the shock produced when water valves shut off quickly. As a result, water hammer arrestors prevent the machines from being permanently damaged.

Do I Need a Water Hammer Arrestor for a Dishwasher?

A dishwasher is one of the appliances with fast-closing valves. Once the washing cycles are complete, the device stops, and the water flow stops too. Due to the sudden water flow stop, your dishwasher can get jammed and stop working. That is where a water hammer arrestor comes in. 

Hammer arrestors will absorb the sudden shock produced when the water shuts off. Water hammer arrestors are ideal for copper and steel pipes. 

Do I Need a Water Hammer Arrestor for a Washing Machine?

A washing machine is also a quick-closing valve appliance. You must control the shock generated when the water flow stops suddenly.

Do Dishwashers/ Washing Machines Need a Water Hammer Arrestor?

All appliances with fast closing valves should be protected from jamming due to the sudden water flow stop. Some machines use an air gap. However, a hammer arrestor is the most effective shock absorber device. 

When installing a dishwasher, a washing machine, or an ice machine, you should invest in a quality hammer arrestor. 

A water hammer arrestor is a device used in fast-closing valve appliances. You, therefore, do not need an arrestor in your shower.

Where Do You Put the Water Hammer Arrestor in the Dishwasher?

If your dishwasher produces a creaking sound when shutting off, it means you are experiencing a water hammer. The water hammer arises when the pressure in the hoses is compromised when the valves shut off suddenly. 

Therefore, you should install the water hammer arrestor directly into the valves. However, other manufacturers advise installing the hammer arrestor at the back of the dishwasher to protect the hoses. 

Where Do You Put the Water Hammer Arrestor in the Washing Machine?

A washing machine also has hoses and valves that shut off when the water stops. The water hammer arrestor is installed in the valves or behind the washer to protect the valves and the hoses from getting damaged. 

Are Water Hammer Arrestors Necessary?

You can use your dishwasher or a washing machine without the hammer arrestor. However, to help prolong the life span of your appliance, you will need to install a hammer arrestor.

A hammer arrestor eliminates the noise produced by your appliance when shutting off. This is because the device balances the pressure to shut off the appliances protecting them from cranking.

You should ensure you are using a hammer arrestor in your appliance. Learning how to install the arrestors is not very hard. You can use the following video for introductory purposes. 

Install Water Hammer Arrestor in a Dishwasher

A water hammer arrestor should be installed between the shutoff valves and the water supply line. The hammer arrestor introduces a cushion of air that aims to balance water pressure and should be installed properly to fulfill its purpose. 

Below are the tools you need to install a water hammer arrestor

  • Pliers
  • Adjustable wrench
  • Pipe wrench

You will also need a high-quality water hammer arrestor. 

Step 1: Locate which valve is producing noise

If your plumber did not install a water hammer arrestor, you could still install it in an existing dishwasher. 

Locate which valves produce huge noise which is caused by water hammer. Sometimes the noise is caused by increased pressure in your supply line. You should measure the pressure of your water to determine if it’s the cause of the banging noise. 

If the water pressure is above 75psi, then that’s the cause. Maintain the pressure around 75psi. You should go ahead to install an arrestor if the pressure is normal. 

Step 2: Shutoff the water supply and disconnect the hoses from the valve

Before starting any DIY project, ensure the dishwasher is disconnected from the supply and electric lines. Be careful not to lose some connectors, such as washers used in a dishwasher. 

Step 3: Connect the water hammer arrestor at the end of a supply valve

Onto each supply valve, thread the hammer arrestor until its hand is tight. You can use the pliers to tighten the valves until you feel some resistance. 

Tightening too much might cause the arrestor the break. 

Step 4: Connect the water hammer arrestor to the hoses

Connect the dishwasher hoses to the hammer arrestor and ensure they are tight enough. Match the hot water hose to the hot water supply line. 

Step 5: Turn on the water back 

After you finish all the installations, you should turn on the water back and test if the water hammer arrestor has solved the issue of the cranking noise. 

To know the arrestor is working as expected, little to no noise will be produced when shutting off the dishwasher.

Install a Water Hammer Arrestor in a Washing Machine

Installing a water hammer arrestor in a washing machine is not any different. Both appliances have shutoff valves and a water supply line. The main difference is the washing machine has a hot and cold water supply line. You will therefore need to have an extra hammer arrestor. 

The water hammer arrestor can be connected directly to the valves or the washing machine. This depends on the manufacturer’s specifications. Otherwise, installing a hammer arrestor in a washing machine differs from installing one in a dishwasher. 

How Do I Stop the Water Hammer in My Dishwasher?

A water hammer arises when water flowing under high pressure suddenly stops. As a result, the valves and the pipes might experience shock, interfering with your dish’s efficiency. To prevent this from happening, you should use a water hammer arrestor. An arrestor introduces a cushion of air that deals with the sudden stop of the water flow. 

Some people use an air gap to stop a water hammer; however, a water hammer arrestor is effective. 

How Do I Stop the Water Hammer in My Washing Machine?

Using an arrestor like the dishwasher, you can stop the water hammer in a washing machine. The arrestor installed between the faucets or on the supply line valves will manage the shock produced when water flow stops faster. 

Where are Water Hammer Arrestors Required?

Water hammer arrestors are installed in appliances that have a fast shutoff valve. These are appliances like a dishwasher, a washing machine, and an ice machine. 

Slow shutoff devices such as showers do not need an arrestor.

Arrestors are also ideal for copper and steel pipes, not plastic and PVC pipes.

Are Water Hammer Arrestors Required with PEX

PEX is a rigid yet flexible pipe. Therefore, in the case of a water hammer in your supply line, PEX pipes are prone to be affected, and the tube may be disconnected. To prevent this, as long as PEX pipes are used with a dishwasher or a washing machine, you will need a hammer arrestor. 

Ensure the hammer arrestor is threaded properly on the male thread of the valve, and use materials like Teflon tape when connecting the arrestor to PEX pipes. 


Installing a water hammer arrestor in your dishwasher or washing machine is not very complicated. However, you will need to know the measurements of both the shutoff valves and the pipes. This is for compatibility. 

Your arrestor might be damaged and need a replacement. Listen to the sound when switching off the machines to know if your appliance needs an arrestor. If the noise is loud, install a water hammer arrestor.

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