Tips for Fixing Water Hammer Problem in Your Home’s Plumbing Pipes

A water hammer problem occurs suddenly, especially when shutting off a kitchen or bathroom tap or any other faucet quickly. It basically produces some sounds through the plumbing pipes.

The sounds are comparable to shock waves. You might even see your plumbing fixtures and faucet vibrate. Such effects show the kind of force and impact that results from the water hammer problem.

Technically, this phenomenon is a form of a hydraulic shock, whereby water sends shock waves that exert immense pressure within pipes.

plumber repairing water hammer problem


A water hammer issue is quite annoying and can lead to damages in the plumbing system. Some water pipes may have old-school techniques for fixing water hammer issue.

However, the best solution to fix this problem is installing water hammer/hydraulic shock arrestor. You can install them in different supply lines of your plumbing system.


Causes of Water Hammer

The hydraulic shock effect of water hammer is the most common and loudest noise issue in plumbing. It usually occurs when plumbing appliances or faucets quickly shut off the water flow into the appliance or fixture.

The speed at which water flow is stopped leads to shockwaves that make the supply lines bang against framing members such as floor joints and wall studs or on each other.

This issue can also result from any other plumbing appliance or fixture, but it’s mostly caused by dishwashers and clothes washers.

These washing machines usually come with solenoid valves. This type of valve shuts off water flow very quickly such that it goes from on to off within a second.


Traditional Solution for Fixing Water Hammer

Older homes usually have water supply lines with pipe fittings known as chambers. These chambers are located on cold and hot water lines near each inlet valve or faucet.

The chambers are hardly visible, except where the room might be unfinished such as in utility rooms. Otherwise, the chambers are hidden within walls along other plumbing lines.

The role of these air chambers is acting like shock absorbers when water flows under high pressure and speed.

Basically, air compresses whereas water doesn’t. As such, the air in the chamber is compressed by the water pressure, making the water pressure halt once the faucet or appliance turns off the water flow quickly.

Shock waves from the highly pressurized water hit the highly compressed air in the chamber rather than hitting the water pipes.

In most cases, the chambers are fabricated and installed on-site before the section where water supply lines reach the faucets. The chambers usually have a length of around 12 inches or longer.

They have similar diameter to that of the pipes. However, if makeshift chambers get filled with water with time, air that functions as the shock absorber gets eliminated.

It’s possible to recharge chambers that are filled with water by simply turning off water supply through the affected pipes and draining any water in the pipes. By so doing, air is allowed to flow back into the chamber to fill it again.

Once the water gets turned on, the air is trapped in the chamber. In case this fails to work, then you should install water hammer/hydraulic shock arrestors near each faucet.


How to Use Water Hammer/Hydraulic Shock Arrestors

The most effective and long-term method of eliminating the problem of water hammer in plumbing lines is installing hydraulic shock arrestors on supply lines that make noise.

These arrestors work like air chambers but come with a sealed gas or air-filled chamber. The seal is usually created by a piston or diaphragm.

The piston or diaphragm moves in case of water hammer, thereby absorbing the shock while ensuring the gas or air and water are separated.

Supplies and Tools Needed

Here’re the supplies and tools you’ll need to install hydraulic shock absorbers:

  • Towel or bucket
  • An adjustable wrench or tongue/groove pliers
  • Water hammer/hydraulic shock arrestors (their number should be as needed)
  • Plumber’s tape


Instructions for Installation:

Step 1: Shut off the main water supply

First, shut off the main water supply or simply the water flow to the dishwasher, toilet, or washing machine using the valve near the fixture or appliance.

Most washing machines come with two valves for shutting off the water flow, one for the cold water line and another for the hot water line. A toilet usually has one valve.

Dishwashers usually have one valve on the hot water line. Simply turn the water valve clockwise until it’s tightly closed to completely stop the water flow between the fixture or appliance and the valve.


Step 2: Disconnect the water supply tubes

Take a towel or bucket and place it around the floor area to catch any water that may spill. Next, disconnect the hose or tube that supplies water to the fixture, appliance, or shutoff valve.

The arrestors should be installed onto the inlet of the fixture or on the appliance or the valve outlet. It’s best installing them closest to the fixture or appliance.

You can use a tongue/groove pliers to loosen tight supply tubes. You can also use a wrench (adjustable one) to loosen any tight compression nut that connects the tube or hose to the valve.


Step 3: Wrap the water inlet or valve male threads with tape

Use plumber’s tape to wrap the water inlet or valve male threads (depending on the area you detached the supply tubing or hose). You can use thread-seal or Teflon tape.

Wrap it clockwise around the threads for three to four times. Next, wrap the arrestor’s male threads with the same plumber’s tape.


Step 4: Install the hydraulic shock arrestors

Take the arrestor and thread it onto the inlet or valve while rotating the female fixture or fitting clockwise until it’s hand-tight.

In case you’re dealing with compression fittings on the toilet or dishwasher valve, fix the tubing of the arrestor into each compression fitting.

Next, slide each compression ring onto the valve. Now thread the arrestor tubing into the fitting while sliding the ring onto the valve.

Next, thread the arrestor onto the compression fitting’s nut. Use a tongue/groove pliers to tighten the arrestor onto the fitting. Use an adjustable pipe wrench to tighten the nut.


Step 5: Reconnect the supply hoses or tubes

Connect each water supply hose or tube to each arrestor. Use tongue/groove pliers or an adjustable pipe wrench to tighten them.

You can now turn on water flow from where you turned it off, be it from the main valve or the valve close to the plumbing fixture. Turn the valve counterclockwise until it’s completely open.

You can flush your toilet or run the dishwasher or washing machine for a cycle to test whether the arrestors are functioning as needed. Check the connections for any leakage. Tighten any leaking connection with a wrench or pliers.


Related Articles:

Finding and Repairing Hidden Leaks in Your Plumbing System

The Basics of Water Pressure Regulators

A Guide on Draining the Plumbing System in Your Home

By |2020-03-28T20:17:23+10:30October 20th, 2019|DIY Plumbing|0 Comments

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