Pipes that bang, hammer, whistle, or rattle when water runs are more than annoying — some causes can damage joints and fittings over time. Understanding what creates the noise leads directly to the fix.

How to Silence Noisy Pipes

Water Hammer (Banging When a Valve Closes)

Water hammer is a loud thud or bang that occurs when a fast-closing valve (like a washing machine solenoid or a single-lever faucet) suddenly stops water flow. The moving water slams to a halt, creating a shockwave that bangs through the pipes.

Fix: Recharge Air Chambers

Most homes have short dead-end pipe sections (air chambers) near fixtures that act as shock absorbers. Over time, water absorbs the air in these chambers, making them ineffective.

Turn off the main water supply
Open all faucets in the house (hot and cold) starting from the highest floor
Let the water drain completely until all faucets stop flowing
Close all faucets, starting from the lowest floor
Turn the main supply back on slowly
Check each faucet — the air chambers should now be recharged

Fix: Install Water Hammer Arrestors

If recharging air chambers does not solve the problem, or if your home does not have them, install water hammer arrestors. These are small devices with a sealed air chamber and piston that install directly on the supply line near the offending fixture (typically the washing machine or dishwasher).

They thread onto the supply valve and cost $10 to $20 each. No soldering — just thread them on like a supply line connector.

Banging or Rattling When Water Runs

If pipes bang or rattle while water is flowing (not just when it stops), the pipes are not properly secured and are vibrating against framing members.

Fix: Secure Loose Pipes

Identify the rattling section by running water and listening along the walls or in the basement/crawl space
Install pipe straps or hangers to secure the pipe to the nearest joist or stud
Use cushioned pipe clamps (with rubber or foam lining) to prevent metal-on-metal contact between the pipe and the clamp
If pipes run through holes in framing, wrap them with pipe insulation where they pass through to prevent rattling

Whistling When Water Runs

A whistling or squealing sound usually indicates a restriction in the water flow.

Causes and Fixes

Partially closed valve: Check all valves on the line (shut-off valves under sinks, main valve, pressure-reducing valve). A valve that is not fully open creates turbulence and noise. Open it fully.

Worn washer or seal in a faucet: A deteriorating washer in a compression faucet can vibrate and whistle as water flows past it. Replace the washer.

Toilet fill valve: A worn fill valve can create a high-pitched whine when the tank refills. Replace the fill valve.

High water pressure: If your water pressure exceeds 80 PSI, it can cause whistling and other noises throughout the plumbing system. Test with a pressure gauge ($10 at hardware stores) attached to an outdoor hose bib. If pressure is too high, install or adjust a pressure-reducing valve on the main supply line.

Ticking or Clicking

Copper pipes expand when hot water flows through them and contract when they cool. If the pipe passes through a tight hole in framing or rests in a tight strap, the expansion creates a ticking or clicking sound.

Fix

Locate the ticking by following the sound along the pipe run
Enlarge the hole slightly where the pipe passes through framing
Wrap the pipe with foam insulation tape at contact points
Replace tight metal straps with cushioned hangers

When to Call a Plumber

If water hammer arrestors do not solve the hammering
If you hear a constant rushing or hissing sound (possible leak inside a wall)
If banging is accompanied by visible pipe movement or leaks
If you are uncomfortable working with supply lines under pressure

Most pipe noises have simple, inexpensive solutions. Address them promptly — the vibration and stress from noisy pipes can loosen joints and cause leaks over time.