Water hammer — the loud bang
Water hammer is a loud bang when a tap or valve shuts fast. The moving water stops suddenly and sends a shock through the pipe. It can happen with washing machines and dishwashers too.
Loose pipes make the noise worse, because they knock against walls. Clipping pipes firmly helps. If the bang continues, a plumber can fit a device that absorbs the shock.
Ticking or clicking when the heating comes on
Pipes expand as they heat up, so they can rub against clips and joists. They may rub against clips, joists or floorboards and make a ticking sound. The noise usually fades as the pipe warms.
It is rarely a danger, yet it can be annoying. A plumber can add padding where pipes pass through wood. Because the cause is simple, the fix often is too.
Rumbling or vibrating from the boiler
A rumble can come from scale or sludge in the boiler or pipes, because water then boils in pockets. Water boils in small pockets and makes a kettle-like sound. This is sometimes called kettling.
Do not ignore it, since it can point to a dirty heat exchanger. Ask a heating engineer to check. Our guide to how to bleed a radiator covers a simple step you can try first.
Hissing from the radiator or pipes
A hiss from a radiator often means air is escaping from a valve. Bleeding the radiator may stop it. Check for leaks too, because steam or spray can hiss.
A hiss from a pipe may point to a pinhole leak. Look for damp patches nearby. If you find water, turn off the supply and call a plumber.
Whistling or whining from the boiler or pipes
A whistle can come from a partly closed valve or a narrow pipe, since water squeezes through a small gap. Water forces its way through a small gap. A tap washer that has worn may also whistle.
Check that valves are fully open. A noisy boiler pump may need attention, so ask an engineer if the sound is loud. Never open boiler parts yourself.
Gurgling in drains
Gurgling means air is moving through a partly blocked pipe, so the drain may need clearing. It can be a sign that the drain needs clearing. It may also point to a venting problem.
If it happens often, find out why. Read our guide to sewer smell in the house, since smells and gurgles often go together.
Banging from the attic tank (older systems)
In older homes, a loft tank can bang when its float valve is worn, because the valve shuts hard. The valve shuts hard as the tank fills. Replace a worn valve to stop the noise.
Working in the loft needs care. Use a torch and stand on joists. If you are unsure, ask a plumber.
When pipe noise indicates a serious problem
Call for help if noises come with leaks, pressure loss or a smell of burning, since these need an expert. Call too if the boiler shows a fault code. These signs need an expert.
If you smell gas, leave the house and call 0800 111 999. Do not wait, because gas is dangerous.
Related guides and local help
If you want to know more, read 5 Common Mistakes to Avoid When a Pipe Bursts at Home. You can also read New Bathroom or En-Suite: A Complete Drainage Planning Guide and 5 Plumbing Checks to Do Before You Leave on Holiday Trips, because they cover closely related problems.
These guides help too: Low Water Pressure: Causes, Diagnosis and Fixes in the UK, Plumbing a Kitchen Extension: What You Need to Know First, Lead Pipes: Health Risks, How to Spot Them and Replacement, Plumbing Jargon Explained: A Homeowner’s Guide to Key Terms and How to Read Your Water Meter and Use It to Spot Leaks. Each one explains a related topic in plain English.
Need help near you? Read our plumbing help page first, or see Plumbing Repairs in Camberley and Plumbing Repairs in Camborne. You can also see Leak Detection in Elland, since every service page has a free quote form. We pass each request to a local drainage engineer.
