Install water hammer arresters to prevent clanking pipes
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Water hammer arrester cutaway
The sliding piston absorbs sudden pressure changes and keeps the pipes from banging.
If your plumbing bangs and clangs like a truckload of scrap metal, you've got “water
hammer.” Water develops momentum as it flows fast through pipes. When a valve
closes quickly and stops the flow, that momentum shakes and pounds pipes. Water
hammer arresters cure this condition with a cushion of air that absorbs the momentum.
Before you install arresters, determine which faucets or valves in your house cause
the noise. Washing machines and dishwashers are prime suspects because their
automatic valves close fast. Arresters for washing machines have screw-on connections,
making them as easy to attach as a garden hose. Other arresters connect
directly to 1/2-in. pipe, often under sinks. You usually have to cut pipes and add tees
to install them. Check the packaging for installation details. Arresters cost about $10
each at home centers and hardware stores.