What is That Bang When I Turn the Tap Off?
That sudden bang is given the term ‘water hammer’. It may not always be a bang, it may be a violent shuddering of the pipes within the walls that may continue for sometime.
Can it be Dealt with Immediately?
It can, by running another tap somewhere in the house or by flushing the toilet. This tends to ease the pressure in the pipes but may not be a long term solution.
So What Causes It?
There are several causes but they generally come from the same source. If you have good pressure in your mains supply the sudden cut off of the flow can cause a bang or vibration. So the answer is that it is due to high water pressure in your plumbing. When it vibrates back through the pipes it can be due to poor fixing of the pipework. It is more common in copper pipes than the present use of plastics and woven covered pipes.
How can I Fix it Permanently?
The addition of a pressure arrestor added to the system, generally in the laundry will help to stop the back pressure. It is no bigger than a cigar and is not intrusive, made of copper or similar material. Basically it collects and relieves the pressure in the system. Consulting a plumber to assess where the pipe requires fixing back and having a pressure test done to ensure the pressure from street is not excessive.
The Homemasters Experience
Water Hammer is a problem that inspectors at Homemasters come across during the inspection of a new home or an older home. The owners will pass it off as nothing and advise that people should not turn the taps off suddenly but turn them off slowly. Under the Australian Standard For Pre purchase Home Inspections plumbing does not have to be commented on as this is the job of a registered plumber. However where things are obvious we will point them out to the client and suggest they have it checked by a licenced plumber.