What Is Water Hammer — And Why Does It Matter?
Water hammer is the sharp bang or thud you hear when a tap is closed quickly or a fast-acting valve (like a dishwasher inlet or washing machine solenoid) shuts off. Moving water has momentum — when it's suddenly stopped, that momentum has to go somewhere. In a plumbing system without proper protection, it becomes a pressure wave that travels through the pipes and slams against bends, fittings, and appliances.
In older Ivanhoe homes — which often have original copper pipe runs with long straight sections and limited flexible connections — water hammer can be severe. The bang you hear is the pressure wave hitting a pipe run, and over time it stresses the joints, loosens fittings, and can cause pinhole leaks in copper pipe over years of repeated impact.
What You're Looking At in This Photo
The photo shows the completed installation: copper pipe runs along the bottom, with a blue-handled ball valve (service isolation) for the supply line, and a Sioux Chief water hammer arrestor — the silver cylindrical canister — installed in line. The Sioux Chief is an industry-standard arrestor used in Australian plumbing. It contains a sealed piston with an air charge on one side: when a pressure wave hits, the piston compresses the air charge, absorbing the energy that would otherwise travel through the pipes.
The ball valve alongside gives isolation for future maintenance without needing to shut off the whole property. Both components are correctly connected into the copper supply line — this is a neat, permanent fix.
What Causes Water Hammer in Ivanhoe Homes
Modern ceramic disc taps close almost instantaneously — unlike the old rubber-washer taps that closed slowly. The faster the close, the bigger the pressure wave.
The solenoid valves on appliances slam shut in milliseconds. A dishwasher filling cycle triggering water hammer repeatedly over years causes real cumulative damage.
Longer runs let pressure waves build more speed. Ivanhoe's older homes with long copper runs from the meter to the kitchen or laundry are particularly susceptible.
Some Ivanhoe properties are on mains pressure above 500kPa — the higher the pressure, the more severe the hammer when flow stops suddenly. A pressure limiting valve can help.
Not all pipe noise is water hammer. Copper pipe expands and contracts as it heats and cools — if hot water pipes pass through tight clips or across hard edges, they tick and creak as they move. This is a different problem with a different solution. We'll confirm what you're actually hearing before recommending any fix.
How Water Hammer Is Fixed
The standard fix is a water hammer arrestor installed at the point where the problem originates — typically near the fast-closing valve causing the shock. We assess where the hammer is coming from (appliance inlet, tap body, or further back in the line) and install the arrestor at the right position.
- Appliance-specific arrestors: For dishwashers and washing machines, a small arrestor is fitted directly to the appliance inlet valve — this catches the shock before it enters the house pipes
- Inline arrestors: For taps and broader pipe sections, a larger inline unit like the Sioux Chief model in the photo is fitted into the supply line at a convenient access point
- Pressure reduction: Where mains pressure is the underlying issue, a pressure limiting valve (PLV) at the meter reduces the system pressure — this dampens hammer throughout the whole property
- Pipe re-securing: Loose or under-supported pipe runs amplify hammer. Re-securing at correct clip spacing reduces the audible transmission through walls and floors
Ignoring Water Hammer — What Eventually Happens
Water hammer is not just a noise nuisance. Repeated pressure waves cause fatigue in copper pipe joints over years, loosen compression fittings, and stress the solenoid valves in appliances — shortening their lifespan. We've seen Ivanhoe homes where years of untreated water hammer contributed to pinhole leaks in the kitchen wall. It's worth fixing properly rather than tolerating.
Banging Pipes in Ivanhoe?
We'll identify the source and install the right fix — water hammer arrestor, PLV, or pipe re-support. Fixed-price, same-day where possible.