4 Causes of Water Hammer

A man adjusts pipes under a sink.

Water hammer is the name given to the loud knocking sound that pipes will often make if there is something wrong with them. There are several reasons this can occur. Here are some of the common causes of water hammer to help you identify what may be wrong with your water supply.

1. Turn Off Supply

Sometimes water hammer will occur if you turn off a water supply very quickly, or if it stops suddenly. To avoid this, be gentle when turning off your pipes. You should also check that the settings on your appliances such as dishwashers and washing machines are correct.

2. Water Hammer Arresters

Water hammer arresters are fitted to the plumbing supply in most homes. They control the pressure in your water supply, making sure that any changes go through gradually. If the water hammer arresters aren't functioning correctly then water hammer can occur.

3. Defective Washers

If any of your faucets have defective washers, water hammer can occur. Make sure that the washers on all your faucets are intact and there has been no erosion.

4. High Water Pressure

If the water pressure in your plumbing system is suddenly too high, water hammer can occur. If you have pressure above 60psi, you may wish to consider installing a pressure reducer.