Step 1 · Diagnose and Locate the Problem

The first step is to confirm the source of the water hammer. Operate fixtures one at a time, such as flushing toilets, running the dishwasher, and starting the washing machine. Listen for the distinct banging or knocking sound that occurs when the water flow is abruptly shut off by a valve. In our assumed scenario, the washing machine's fast-acting solenoid valves are the culprits. You will need to install an arrestor on both the hot and cold water supply lines leading to the machine for the best results.