how a water hammer worksIt is a common problem to have noisy pipes when the water pressure is turned on or off. This banging or “hammering” can be very disruptive and annoying, not only for you but in extreme cases, also for your neighbours. We spoke with our friends at LJM Plumbing to find out more about how to fix this problem.

This noisy banging is called Water Hammer or Hydraulic Shock, and it’s caused by an excessive sudden change of water pressure surging through your pipes, constantly crashing into the valve that has been turned off. This makes the pipes bang against wall studs or rattle in loose mounting straps. Other causes can be flick mixer taps turning off abruptly; solenoid valves on appliances – washing machines and dishwashers being an example, or in older homes – pipes deteriorating and/or decaying tap washers. Too high a water pressure can also cause clanging, banging and whining.

If left unchecked water hammering can damage joints and valve connections in your pipework, causing expensive repairs in the future.

What can you do?

Check Your Air Chamber

This is a vertical pipe in the wall cavity usually near where the water pipe comes out from the wall. It absorbs the fast moving water pressure before it bangs against the end of the pipe. The air chamber will not be able to be physically inspected, so what you can do is:

  1. Close your water supply valve
  2. Turn on the highest point tap inside the house.
  3. Drain ALL the water from the lowest tap that is located either inside or outside your house. When all the water is drained, air will replace it.
  4. Once all the water is drained from the pipes through the lowest tap, turn it off and reopen the main water supply valve.
  5. Air will purge out of the pipes causing a spluttering noise, this should eliminate the water hammer noise.

If this doesn’t work install an anti-hammer tap valve or hammer relief valve, you may have to check your plumbing regulations before your attempt this, or call your local plumber.

How to Adjust your Water Pressure if it’s too High

If your home is modern, it may have a regulator located where the main water supply comes into your home.

Modern homes have a regulator mounted at the location where the main water supply enters the home which you could adjust. To test your water pressure, get a water pressure gauge that attaches onto the hose top, then use a wrench or screwdriver to adjust the pressure.

If there is no regulator, it would be best to get a plumber to install one for you.

By getting a regulator installed, it will eliminate whining and noisy pipes and also eliminate damage to washing machines, dishwashers, ice makers in your fridge and other appliances supplied with water.