Why Do My Pipes Bang When the Washing Machine is On?
Loud banging pipes when a washing machine fills or a tap is turned off is caused by a hydraulic shockwave called water hammer. This happens because modern washing machines use fast-acting solenoid valves that shut off the water supply instantly, sending a shockwave crashing back through your unclipped pipework.
What Damage Can Water Hammer Cause?
It is not just a nuisance. Repeated shockwaves can loosen pipe fittings, weaken solder joints, and eventually lead to hidden leaks under floors or in walls. The constant vibrating and crashing causes mechanical stress to your plumbing system.
Listen to an example of severe water hammer caused by modern appliances and taps:
Two Ways to Stop Banging Pipes
Step 1: Check Pipe Clips (DIY)
Check visible pipework (under the sink or near the boiler) to see if the pipes are loose and hitting against the wall. Sometimes, simply adding a few pipe clips to secure the pipes tightly to the wall or joists can resolve minor rattling.
Step 2: Install a Shock Arrestor (Professional Fix)
The definitive cure for washing machine water hammer is installing a mini expansion vessel—also known as a shock arrestor—on the supply pipework. This device contains a pressurized air bladder that absorbs the shockwave when the valve shuts, preventing the energy from traveling through your pipes.
Stop Water Hammer in Crawley
If your pipework is rattling every time you run a wash, Mend Your Home can silence it. We routinely install shock arrestors and secure loose pipework for homeowners across Crawley and West Sussex to prevent long-term damage.
Need to Fix Your Noisy Pipes?
Don't wait for a leak to happen. Call your local plumbing experts today.
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