What is water hammer?
Water hammer is a loud banging sound and sudden pressure spike that occurs in plumbing pipes when fast-moving water is abruptly halted, typically by a valve closing quickly.
When water rushing through a pipe comes to a sudden stop, the momentum creates a shockwave that reverberates back through the system, producing a distinctive banging or clanging noise. This phenomenon is called water hammer. The pressure surge can reach several times the normal operating pressure in your pipes, potentially damaging fittings, valves, and connections over time.
In homes throughout Klang Valley, water hammer most often occurs when a tap or appliance valve closes rapidly. Common triggers include washing machine inlet valves shutting off after a cycle, dishwasher fill cycles, or quick-closing kitchen or bathroom faucets. The problem becomes more noticeable in older properties or where water pressure is already elevated.
Plumbers address water hammer using two main approaches. An air chamber is a vertical pipe section filled with air that compresses when the pressure spike hits, absorbing the shock. A water hammer arrestor serves the same function but uses a sealed chamber with a spring or bladder mechanism, making it more reliable and space-efficient. Both devices should be installed near the point where the surge originates, such as behind washing machine connections or under sinks.
Neglecting water hammer can lead to loose connections, valve deterioration, and leaks. If you hear regular banging in your pipes, a plumbing professional can identify the source and install the appropriate dampening device.