Water Hammer: Why Your Pipes Bang and How to Stop It
That loud bang when the washing machine finishes filling isn't just annoying — it's a pressure shockwave that will eventually crack a fitting. Here's what causes water hammer in Brisbane homes and how we fix it.
What Water Hammer Actually Is
When a valve slams shut (dishwasher, washing machine, mixer tap), the moving column of water hits the closed valve and bounces back through the pipe. Without cushioning, the shockwave rattles copper against timber framing.
Common Brisbane Causes
High mains pressure (Urban Utilities regularly runs 700–900 kPa), failed arrestors on solenoid appliances, loose pipe clips in wall cavities, and worn washers in jumper-valve taps.
Quick DIY Checks
Turn off appliances one at a time to identify the culprit. Check that pipe clips under the house are tight. Replace any perished tap washers.
Permanent Fixes
Fit a pressure limiting valve (PLV) at the meter — Queensland Plumbing Code requires ≤500 kPa at outlets. Install mini hammer arrestors on washing machine and dishwasher taps. Refix loose pipework.
Frequently Asked Questions
Can water hammer burst a pipe?
Yes — sustained hammer fatigues soldered joints and push-fit fittings. We regularly repair burst copper directly caused by years of untreated hammer.
How much is a PLV installation?
Typically $280–$450 supplied and fitted at the meter for a standard Brisbane home.