Water Hammering: Causes, Effects, and Prevention

By: Ben Ciolino

Have you ever heard that loud bang or rattling sound after turning off a faucet too quickly? Well, you might have just encountered water hammering. This common plumbing issue, also called hydraulic shock, can create serious problems in your home or industrial facility if left unchecked.

Water hammering happens when water traveling through pipes suddenly comes to a halt or changes direction. This quick stoppage creates a pressure wave that can damage your plumbing system and even cause pipes to burst.

In this blog, we’ll break down everything you need to know about water hammering, from how it occurs to effective solutions to prevent it.

What is Water Hammering?

Water hammering, or hydraulic shock, occurs when a sudden change in the flow of water or steam through a piping system creates a pressure surge. This can happen when a valve closes abruptly, or a pump shuts off, causing water to slam into a closed valve or reverse its direction rapidly. Since water is incompressible, the shock wave travels through the pipes, often accompanied by a banging noise, much like the sound of a hammer striking the pipe—hence the term “water hammer.”

Causes of Water Hammering

Water hammering can occur due to several reasons, but the most common causes include:

• Sudden Valve Closure: When a valve is closed too quickly, the moving water suddenly halts, creating a shock wave that reverberates through the pipes.
• Pump Shutdown: If a pump that circulates water in a system stops abruptly, the water flow reverses, leading to pressure spikes and hydraulic shock.
• High Fluid Velocity: When the velocity of water in the pipes is too high, any sudden stoppage creates intense pressure waves that are transmitted through the entire system.
• Non-Return Valve Issues: In systems with submersible pumps, non-return (or check) valves prevent water from flowing back into the pump. If these valves close too quickly or malfunction, they can contribute to water hammering by causing sudden back-and-forth pressure surges.

Why You Should Worry About Water Hammering

While the noise alone can be annoying, the real dangers of water hammering lie in the damage it can cause to your pipes and plumbing system. If not addressed, water hammering can lead to:

1. Pump and System Damage

Water hammering can gradually wear down pumps, valves, and other system components, leading to costly repairs. Continuous pressure surges can weaken the structure of gaskets, seals, and even pipe joints.

2. Leaks

Over time, the repetitive impact of hydraulic shock can loosen fittings and joints, leading to leaks. While small leaks may not seem like a big deal, they can go unnoticed and worsen over time, potentially damaging surrounding equipment or property.

3. Ruptured Pipes

In extreme cases, water hammering can cause pipes to burst due to excessive pressure. Repairing ruptured pipelines can be expensive and time-consuming, requiring you to replace not only the damaged sections but possibly entire system components.

4. Property Damage

If water hammering causes leaks or pipe ruptures, the water can damage floors, walls, and electrical equipment. This is especially dangerous in industrial settings, where flooding and electrical malfunctions can lead to workplace accidents.

5. Downtime

In both residential and commercial setups, dealing with water hammer damage can lead to costly downtime. For businesses, especially in process industries like food and beverage or manufacturing, this can mean major financial losses due to system failure and halted production.

How to Prevent Water Hammering

The good news is that water hammering is entirely preventable with the right strategies. Here are some tried-and-true methods for stopping it before it wreaks havoc on your pipes:

1. Install Silent or Spring-Assisted Check Valves

One of the easiest ways to prevent water hammer is to use silent check valves. These valves close gradually, unlike traditional check valves that slam shut and create pressure surges. Spring-assisted check valves, in particular, gently close before water can reverse flow, reducing the risk of hydraulic shock.

2. Air Chambers

Air chambers act as shock absorbers, cushioning the water when it changes direction abruptly. These chambers are essentially vertical pipes attached to your plumbing system that contain air pockets. When water slams into a closed valve, the air pocket compresses, absorbing the force and preventing the shock wave from traveling through the system.

3. Water Hammer Arrestors

For a more advanced solution, installing water hammer arrestors is an effective long-term fix. Unlike air chambers, arrestors use a spring and piston system inside a sealed unit to absorb the shock wave created by sudden water stoppages. They don’t need maintenance and can be installed in various positions.

4. Proper Pipe Support

Loose pipes are more likely to create noise and vibrations when subjected to hydraulic shock. Make sure all pipes are securely fastened to walls or other support structures. Pipe clamps or straps can help stabilize the plumbing and reduce the effects of water hammer.

5. Pressure Regulators

High water pressure increases the chance of water hammer. Installing a pressure regulator can help reduce the pressure in your system to a safer level. This also prolongs the life of your plumbing fixtures and reduces overall stress on the system.

6. Gradual Valve Closure

One of the easiest things you can do is simply be mindful of how quickly you close your faucets or valves. Closing valves slowly allows the water to decelerate gradually, reducing the chances of water hammer.

Final Thoughts

Water hammering might seem like a minor inconvenience at first, but it can lead to serious and costly problems if ignored. Understanding what causes hydraulic shock, recognizing the signs of water hammer, and taking preventive measures are essential steps to maintaining the health of your plumbing system. Whether it’s installing a water hammer arrestor or simply securing loose pipes, proactive steps can save you from the headache of costly repairs and property damage.

If you’ve noticed any signs in your home or facility, don’t wait for it to escalate into a bigger issue. Taking quick action now can save you both time and money down the road.

Call 1-Tom-Plumber 

Don’t hesitate to contact us here or call us at 1-Tom-Plumber (1-866-758-6237) if you need any plumbing, drain cleaning, water damage, or excavation service. 1-Tom-Plumber’s certified team of plumbers and drain technicians respond immediately to any emergency plumbing, drain cleaning, or water damage problem. We also handle the excavation of underground water lines and sewer main lines. Our immediate-response team is available every day and night of the year, even on holidays.