Noisy Banging Water Pipes

How to Resolve Problems with Pipes

Annoying problems

Do your pipes make a banging sound when a tap is turned off, or when the dishwasher suddenly stops drawing water? Then you may have something known as water hammer, which can occur when the air chambers installed in a system no longer work. Other symptoms may be loose mounting clips or high water pressure.

The best way to understand why a pipe will make a sudden banging sound is to imagine a fast flowing stream of water moving along a narrow pipe. All of a sudden a valve is closed and the water has to come to an abrupt stop which results in a loud thud. The noise is carried through the system of pipes and can be heard all over the house. Besides being annoying, the hammering action can damage the joints and connections of the pipework and lead to leaking water pipes (linked).

Noisy water pipes can cause great annoyance

Noisy water pipes can cause great annoyance

Air chambers

For that reason it is good practice to build air chambers (water hammer arrestor device they can be purchased from a good plumbing supplier) into the system which will absorb the shock as the fast moving water stops suddenly. These should be located in vertical runs of pipe and at critical locations in the system, such as washing machines and dishwashers; in fact most of the places where shut-off valves are installed.

In order to eliminate the cause of water hammer you will need to allow the air chambers to be replenished by following this procedure:

 Air locks can cause a loss of pressure

Air locks can cause a loss of pressure

1.     Shut off the main stop cock or water valve.

2.     Open the taps at the highest point of the house.

3.     Find the tap at the lowest point and turn that on to allow the water to drain from the pipes. (It may be the outside tap that is lowest).

4.     Once the water has completely drained turn off the lowest tap and re-opens the stop cock.

As the air pushes out of the horizontal and vertical pipes it will sputter, but some air will remain in the air chambers replenishing the air needed to eliminate water hammer.

Pipes can be a nuisance when they are not secured properly

Pipes can be a nuisance when they are not secured properly

Loose clips

If the banging pipes sounds more like a continuous vibration it may be caused by loose pipe clips. Most of these are in the form of plastic half circles that grip the pipe and hold it in place. Locating the source of the problem can be difficult and it may require a process of elimination to find the exact spot where the pipe is vibrating or banging. This can be made harder if the pipes are boxed in and can sometimes mean making an opening in a perfectly good wall to access the problem. Sometimes it is possible to fix new clips close to the problem and at more accessible points which may eliminate the noise. Don’t think about just living with the problem as there is the potential for the vibrations to loosen the pipes and cause far greater problems.

A water pressure tank that malfunctions can cause noisy pipe issues

A water pressure tank that malfunctions can cause noisy pipe issues

Pipes fitted to tightly

If your heating pipes are fitted under timber floors and squeak the most probable cause is the pipe being laid to tightly. I will explain – the floor joist (the timber that supports the floor boards) will be notched out so the pipes can be laid.  If the notches have not been lined the copper pipes can squeak when they expand and contract. If you have this problem it can be a devil to sort as you will to trace the pipes and lift the flooring – widen the notches and then line them (a rag based pipe sleeving is ideal for this) tracing the pipe runs is easy with using a pipe tracing metal detector they are available from most DIY stores- you need to spend in excess of £25.00 for a decent one.  The squeaking is often at its worst during initial heating and final cooling- so most people just put up with it.

High water pressure

Another possible cause of banging pipes can simply be a case of water pressure that is too high. You can go to the expense of having a pressure regulator valve installed but it can cost several hundred pounds to have one installed professionally. On the other hand it has the potential to save you a lot of money as high water pressure can cause damage to water fed appliances.


  • It is possible to test the water pressure by screwing a water pressure gauge onto a hose bib, or you may find that your water company will test the pressure for you
  • It can also be a good idea to turn your stop cock valve off by a quarter turn once it is fully turned on


Image credit: William herron