A well-functioning heating system should work almost silently. But when your pipes or boiler make loud noises, it will keep you up at night. So which noises are normal, and which should you be worried about?

We’ll walk you through the possible causes and how you can stop the noise before it turns into something worse.

How to identify the problem

Listen for unusual sounds

It’s normal to hear a faint whooshing noise from your pipes, particularly when you turn on a tap or use the shower. The sounds you might need to pay more attention to are:

  • Gurgling
  • Whistling
  • Banging
  • Clunking
  • Rattling
  • Humming

These could point to issues like faulty radiator valves, limescale buildup, loose pipes or incorrect boiler pressure. In some cases, you might be able to find and fix the issue yourself. But if the problem isn’t obvious, we recommend contacting a professional plumber. Otherwise, you might risk damaging your heating by mistake.

By the way, it’s also worth checking for any activity on the water network in your area. If there’s been a burst water main or planned works, for example, that could explain the unusual noises.

Inspect your pipes

It might be that the noise comes from a particular room or radiator in your property. If so, look at the pipes there – do they seem loose, or are they vibrating?

Other things to check for are:

  • Leaks: common signs are dampness on walls and floors near your pipes, and green stains on copper piping
  • Loose valves: get some paper and pat it around your radiators to spot where any moisture is escaping
  • Blockages: in cold weather, your boiler’s condensate pipe can get frozen – go outside and take a look (it comes out through an external wall near the boiler)

Here’s our quick guide to fixing a frozen condensate pipe.

Check your heating setup

Your boiler is the heart of your heating system, so it might play a role in the sounds you’re hearing. Equally, there might be something wrong with the settings on your radiators. Here are a few areas to check:

  • Pilot light (if your boiler has one): look at the small window on the front of your boiler – if you can’t see the pilot light, you’ll need to reset it
  • Boiler pressure: see the gauge on your boiler – it should be between 1 and 2 bar (but check your manual for precise details)
  • Cold radiators: if they’re not heating up or taking a long time, there might be air or sludge in the system

Find out more about how to spot and solve radiator problems.

Common fixes for noisy pipes and boilers

Before you call a plumber, there are some possible causes you can eliminate yourself. 

On the other hand, please don’t attempt anything that seems risky or likely to cause damage. If in doubt, always get help from a heating professional.

Air in the system

Air in your pipes and radiators can cause clicking, tapping or gurgling sounds. Your radiators also won’t heat up very well, because they aren’t completely full of water.

To solve this, it might be as simple as bleeding your radiators. That should let the air escape from your heating system and banish the strange sounds. If you don’t know how to do this, see our step-by-step radiator troubleshooting advice.

Boiler kettling

The term ‘kettling’ comes from a whistling sound in the boiler. This is caused by a buildup of limescale, which can happen in hard water areas. When there are minerals like calcium in the water supply, they leave a chalky residue behind. You may have noticed this in your kettle, but you can’t see it in your boiler, of course.

Some other symptoms of limescale are radiators that are cold at the bottom and tapping noises in your pipes.

Important: a whistling boiler can be dangerous. The limescale buildup creates extra heat and pressure which can damage internal parts. You can book a repair now with a Gas Safe registered engineer.

Loose pipework

Your pipes carry moving water, so if they’re loose at any point they can rattle or vibrate. It might be that the pipes weren’t fitted properly or they’ve come loose over time. Either way, this should be fixed before it causes any damage.

Once you’ve identified the pipe making the noise, try tightening or replacing any loose fittings. Sometimes you might need professional help, such as if the pipes aren’t accessible or need to take a different route.

Water hammer

If you hear bangs or thuds from your pipes, it might be what’s called ‘water hammer’. This is more common in properties built since the late 1990s, because of modern discs and valves. These pipes have air chambers, which stop water hitting the valves when you turn the tap off. Over time the air chambers can fill with water, meaning they don’t cushion the valves anymore. That’s when the thudding noise happens.

To fix this, you need to put air back in those protective chambers. Here’s how:

  • Turn off your water supply at the mains stopcock
  • Turn on all the taps on the top floor
  • Turn on all the taps on the bottom floor
  • Let all the water drain out, so the pipes are empty
  • When no more water is coming out of the taps, turn the mains stopcock back on
  • Don’t turn the taps off yet – let water come out of each one
  • Finally, turn off the taps

This should replenish the air in the chambers and get rid of that thudding noise.

High boiler pressure

If the water in your pipes is too pressurised, that can make noise as it bangs into things like valves. Check your boiler manual to see what pressure it should be. Most boilers have a pressure gauge on the front, so you can see if it’s within the normal range.

High boiler pressure can be a serious issue, so it’s worth having it looked at by a Gas Safe registered engineer. To reduce the pressure in the meantime, all you need to do is bleed a radiator. Find out how in our radiator maintenance guide.

Some mains water supplies can also be over-pressurised. If that’s the case, you might need a pressure reducing valve (PRV) installed. These automatically reduce the mains pressure to the right level for your property. You’ll need a plumbing professional to put one of these in.

Contact us for further support

If you’re at all unsure how the advice here applies to your heating, don’t try it yourself. Making a mistake with your plumbing can be costly and potentially dangerous.

It’s easy to book a repair with us, and you don’t need a Domestic & General plan. Arrange your visit with an expert boiler engineer

About the author

Josh Allen

Josh is a copywriter at Domestic & General who works across our digital journeys and beyond. Starting out in journalism and travel writing 10 years ago, he's since turned his hand to technology and insurance. Josh is also a published short story writer with a novel in the works, and he's known to twang a tune on the guitar and banjo.

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