water hammer
n.— «It sounds as if the condition which you are describing is a perfect example of what is called “water hammer.” This noise generally occurs when you turn off the water at a faucet or an appliance quickly. The water in the pipes slams to an abrupt stop, causing this hammering noise.» —“Banging faucet” by Morris Carey, James Carey Mexia Daily News (Texas) Mar. 12, 2008. (source: Double-Tongued Dictionary)