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1. 1. What is water hammer?

• Water hammer, also known as hydraulic shock, is a banging or knocking sound that can occur in a water pipe.

2. 2. What causes water hammer?

• Water hammer occurs when the water in the pipe suddenly changes direction, for example when a faucet is turned off. The change in direction creates pressure waves, which can vibrate and “bang” on the pipe, and can cause damage if the pressure is too high. Other causes of water hammer include air trapped in pipes, plumbing design problems (such as poor/improper installation, incorrect fittings used, etc.), and plumbing maintenance problems (such as kinks, corrosion, or other damage to pipes, improper water pressure settings, etc.).

3. 3. How can I stop or prevent water hammer?

• One of the simplest ways to minimize water hammer is to turn on the tap at the highest fixture on your property – often an upstairs or attic bathroom. In homes where these upper bathrooms are rarely or never used, it is a good idea to run the tap for one or two minutes every couple weeks. Other solutions include installing a pressure reducing valve or multiple air chambers. Please note, these solutions are more costly and complex, and customers should consult a qualified licensed plumber for more advice.