What phenomenon is described as a surge in pressure caused by suddenly stopping the flow of water?

The phenomenon described as a surge in pressure caused by suddenly stopping the flow of water is known as water hammer. When water flowing through pipes is forcibly stopped—such as when a valve is quickly closed or a faucet is shut off—the momentum of the moving water creates a shock wave that results in a sudden increase in pressure. This can lead to loud banging noises and can potentially cause damage to pipes, fixtures, and appliances if the pressure surge is strong enough.

Understanding water hammer is crucial for plumbing and fire protection systems, as it helps in designing systems that can withstand or mitigate the effects of such pressure surges.