Water hammer is an annoying, banging sound made when a tap is turned off. It can also occur after water has stopped filling your washing machine or dishwasher.
The sound can be loud and disruptive and is an indication of a plumbing problem which needs to be resolved.
How does water hammer occur?
Water hammer is also known as hydraulic shock. When a valve or water appliance is turned off, it can increase pressure in the pipes which causes the water to vibrate against the inner walls of the pipe or bang against the valve which shut off the water. The sudden change of water direction can cause the pipe to bang against frames or walls due to the hydraulic shock.
Water hammer can occur in these situations:
- Water pipes which haven’t been secured correctly with brackets
- High water pressure
- A strong appliance with no pressure limiting valve
- Faulty jumper valve or deteriorated washers
- Air trap in pipes
Why is water hammer a cause for concern?
Water hammer is a problem which shouldn’t be ignored and is best solved by a licensed plumber.
If water hammer is left for too long, it can cause a burst pipe or affect the appliance or valve due to the constant shock. This can be costly to fix, and could have been avoided if investigated earlier.
How to fix water hammer
It can take time for a plumber to diagnose the cause of the water hammer and it may require a few experiments to completely eradicate the noise altogether.
For older homes, it’s most common on taps when the jumper valve or washers need to be replaced.
In modern or renovated homes where DIY plumbing may have taken place, it can be the way the pipes were installed with a lack of brackets to support the water pipes.
A water hammer arrestor is a common fitting used to fix this problem, but it’s often installed when all other avenues have been explored.
Can water hammer be fixed by a homeowner?
Water hammer is a problem best left for a licensed plumber to solve. It may involve cutting into water pipes or changing or adding valves to assist with the pressure in the pipes. Any maintenance or repairs to a home’s water line should be completed by a licensed plumber.