Loud banging or knocking noises when you turn off a tap are usually caused by water hammer. This happens when flowing water is forced to stop suddenly, creating a pressure shock inside the pipes.
Common causes
Fast-closing taps or appliances, high water pressure, trapped air, and loose pipework are the most common triggers. Older homes and poorly clipped pipes are especially prone to noise.
In some cases, failing valves or worn stopcocks can make the problem worse.
What you can try
Securing loose pipes can often reduce banging. Draining the system and refilling it slowly may restore air cushions that absorb pressure shocks. Reducing excessive water pressure can also help protect your plumbing.
When to call a professional
If banging is loud, frequent, or getting worse, professional assessment is recommended. Persistent water hammer can damage joints and fittings over time.
Calore can diagnose the cause and install the correct long-term solution, whether that’s securing pipework, fitting pressure-reducing valves, or addressing faulty components.