Water hammer – What it is and what to do

Let me set the scene. Its 2 o’clock in the morning and nature is calling. You unwillingly drag yourself out of bed and head for the bathroom hoping you don’t stub your toe on that damn chair again. You do your business, then proceed to wash your hands. But as the you turn the tap off, suddenly you hear a banging and clanging noise. Is it the ghost that your sister was talking about? Is somebody breaking in? Maybe… But its most probably just a case of water hammer.

So what is water hammer?

Essentially water hammer is a banging and vibrating sound that occurs in your water service pipework; it usually occurs in a similar fashion to the above scenario. When a tap is running and is suddenly closed, it will cause hydraulic shock waves throughout the pipework until the energy dissipates. Think of a row of people running through a doorway and suddenly the door closes, those people will crash into each other one by one and most likely will bounce off the walls, this is what’s happening inside your pipework. More often than not, the noise is a harmless annoyance, however with high pressure water and weak pipework joins, a burst can occur.

What causes water hammer?

There are several causes to water hammer such as:

  • High water pressure
  • Faulty tap washers
  • Poorly secured pipework
  • Flip mixer taps
  • Solenoids on washing machines

What to do

Before you give us a call, there are a few things you can try yourself which may work.

Firstly have a check around your home for any copper pipework that may be loose and in need of fastening. If it is safely accessible, try to secure the pipe and see if that stops the hammer. A lot of the time, water services are installed in the ceiling, so if you don’t feel safe going up there, you can always call a professional.

If the noise is only in a particular area, then check the tap washers in that area as they may be faulty and in need of replacing. If you want to change them yourself, then go for the brass/copper soft turn washers and avoid the cheap plastic alternative.

So you’ve secured the pipework and changed the washers but the rattling persists…now what? Well it sounds like you need some professional assistance. Contact your local plumber and if they know what they’re doing, then they can rectify the issue but installing pressure reduction valves or water hammer arrestors for example. A licenced plumber with excellent problem solving skills will silence your pipework and clear your mind.

We hope you’ve found this article useful. Be sure to check out the rest of our blog for more tips and useful information. As always for any questions or quote enquires, feel free to contact us, we’re here to help.



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