Water Hammers: Hazards, Causes, & Solutions

Your household plumbing system should operate quietly. If you often hear a loud knocking noise when shutting off a water fixture in your home, then that is a sign that you may have a common plumbing problem called a water hammer.

Water hammers typically occur when water in a home plumbing system suddenly changes direction or pressure in a home water pipes increases suddenly, causing pipe hydraulic shock. This shock can cause pipes to vibrate and bang against each other or against interior components of your walls, creating this knocking sound or even causing your home walls to vibrate.

Read on learn about water hammer hazards, along with their numerous causes and solutions.

Water Hammer Hazards

A water hammer can be a symptom of an underlying plumbing system problem, and allowing pipes to vibrate and bang against each other for an extended period of time can lead to even more plumbing problems.

As pipes shake and knock against each other, pipe connections can loosen and joints can deteriorate. When pipe connections are no longer secure, water can begin leaking at these connection sites. Water leaks that occur inside of walls often go unnoticed until water begins seeping into interior living spaces and causing extensive damage.

Water Hammer Causes & Solutions

Many home plumbing and appliance problems can lead to the development of water hammers.

Water in Plumbing Air Chambers

Homes built before the 1960s typically have plumbing systems equipped with air chambers, which are pipe sections filled with air. These chambers help regulate pipe water pressure to limit water hammer occurrence. Over time, air chambers can fill with water, limiting their ability to prevent water hammers.

Thankfully, most homeowners can remove water from plumbing air chambers easily. First, shut off your home’s main water supply valve. Then, run all of your water fixtures until all water is drained from your home plumbing system. Finally, turn your main water supply valve back on.

Draining your entire home plumbing system typically removes all water from air chambers to help them begin performing their task properly again.

Loose Water Supply Lines or Old, Unstable Pipes

Some water hammers are caused by loose water supply lines or old pipes that are no longer secured to the home’s framework properly. When pipes are not secured to the home’s framework properly, they can move around and create noise as water flows through them.

If you suspect your water hammers are caused by old pipes lacking their proper fasteners, then have a plumber come inspect your plumbing system and attach fasteners where needed to stop water hammers.

High Water Pressure

While low water pressure can be an annoyance, water pressure that is too high can exert pressure on your pipes that can create numerous problems, including water hammers. Ideally, your water pressure should not exceed 80 pounds per square inch (PSI) to limit water hammer occurrence.

You can test your water pressure with a kit you can purchase at a local hardware store. If your water pressure exceeds 80 PSI, then have a licensed plumber add a pressure regulator to your home’s main water supply line to reduce water hammer occurrence.

Appliance Problem

If a water hammer occurs in your home only when you run one specific appliance, such as a garbage disposal, then the water hammer may be caused by the appliance. Washing machines and dishwashers often cause water hammers because their water valves close very quickly.

To stop a water hammer caused by a single home appliance, have a plumber install a fixture called a water hammer arrestor on the appliance or water line that serves it. A water hammer arrestor contains a cushion of air that absorbs hydraulic shock that can cause water hammers as the appliance water valve closes.

If you hear a knocking sound when you shut off a water fixture, you likely have a plumbing water hammer that could lead to a leaky pipe if it is not remedied. Contact the experts at Moon Valley Plumbing and Rooter for plumbing repairs needed to stop your water hammer problem today.