Water Hammer: Causes, Risks and How to Fix It

Water hammer is the familiar loud “bang” or “hammering” sound that can happen in home plumbing systems when a faucet closes, a valve shifts, or a supply line experiences a sudden change in flow. The noise comes from pressure waves traveling through the pipes—an effect similar to what you’d feel if you abruptly stopped moving water in a moving pipe network.

Although it may seem like a minor annoyance, water hammer can indicate pressure and flow conditions that may gradually damage plumbing components. Understanding why it happens is the first step toward fixing it safely and preventing repeat incidents.