Symptoms
- Loud bang from the walls when the washer starts or stops filling
- Noise happens at consistent points in the fill cycle
- Other appliances with solenoid valves may cause similar noise
- Pipes may visibly shake with the noise
Likely causes
- CommonFast-closing solenoid valve creating a pressure shock waveModern washer valves close very quickly, and without cushioning, this can send a shock through rigid pipes.
- CommonLoose or unsecured pipes amplifying the noisePipes not properly strapped to framing can bang against studs when the shock wave hits.
- PossibleMissing or failed water hammer arrestorHomes without this device, or with one that's failed, are more prone to noticeable water hammer.
- PossibleHigh household water pressureExcess pressure intensifies the shock wave when a valve closes suddenly.
What to do
- Note if the bang happens specifically when the washer starts filling, stops filling, or both.
- Check accessible pipes for looseness against framing and secure with pipe straps if found.
- Consider having a plumber install a water hammer arrestor near the washer's supply valves if one isn't present.
- Have your home's water pressure checked; pressure above 80 psi may benefit from a pressure-reducing valve.
- This is generally a plumbing issue rather than something inside the washer itself.
- If bangs are severe or frequent, address it soon since repeated shock can loosen pipe joints over time.
Tools and parts
Water hammer arrestorSearch: “water hammer arrestor washing machine”
When to call a pro
A plumber can install a water hammer arrestor and check your home's water pressure if banging continues.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.