Quick Answer:
If you hear a hammering or banging when the ice maker stops filling, it’s usually a rapid valve shutoff or a loose pipe that’s transmitting a pressure spike. Run the ice maker cycle to confirm the timing, feel nearby supply lines for vibration, and compare the sound to other appliances. If the noise comes from inaccessible piping or built-in systems, a plumber can safely isolate and fix it.
Why This Happens
Most ice makers use a small solenoid valve that opens to fill the tray and closes quickly once full. When a valve closes rapidly it can create a pressure spike in the water line — the familiar “water hammer” — or it can make nearby pipes vibrate against cabinets or framing. Small-diameter lines and tight runs inside walls or under appliances can make the noise louder and harder to trace. Built-in equipment such as water softeners, pumps, or an autofill system can add valves or check valves that produce similar sounds, so comparing cycles helps narrow the source.
Step-by-Step What to Do
1. Run the cycle that triggers the sound
- Start a normal ice-making cycle or let the unit run until it fills and finishes. If your model has a test or fill button, use that so you can repeat the event on purpose.
- Do this while someone else is nearby to help observe or record where the sound seems loudest.
2. Listen for the exact phase
- Note whether the noise happens during fill (water flowing), during drain (if the model drains), or at shutoff (when the valve clicks closed). The shutoff phase is the most likely to cause a hammering sound.
- Try to time it: “fills for X seconds, then bang at shutoff.” That detail helps a technician diagnose remotely if you call one.
3. Touch nearby supply lines
- Carefully reach to the visible supply line and fittings while the cycle runs. Feel for vibration, thumps, or a sharp knock when the valve closes. Use the back of your hand to avoid sudden movement that could cause injury.
- If the pipe or valve is warm or wet, stop and dry the area before proceeding. Don’t force access into tight spaces.
4. Compare with other appliance cycles
- Run the washing machine, dishwasher, or other fixtures on a fill cycle and listen for similar knocks. This helps tell whether the problem is isolated to the ice maker or a whole-house piping issue.
- If the sound is similar to other known events, such as Pipes vibrate during clothes wash or Hammer when pool autofill runs, note that similarity — it points to a pressure or valve issue rather than a single defective appliance.
5. Check accessible supports and try a simple fix
- If you can see the pipe and its mounting clips from the outside, tighten any loose straps or add a cushion where the pipe rubs. Small rattles sometimes become loud when amplified by a cabinet or panel.
- Do not remove covers, disconnect lines, or take apart the appliance to reach hidden sections.
What Not to Do
- Don’t disassemble the ice maker, its valve, or any built-in appliance components to chase a noise. Internal parts can be delicate and under pressure.
- Don’t bypass safety devices, remove check valves, or alter controls to try to stop the sound. That can create leaks, flooding, or unsafe conditions.
- If the noise is tied to built-in systems like water softeners, pumps, or in-wall auto-fill devices, don’t attempt to service those yourself — have a plumber diagnose and repair them properly.
When to Call a Professional
- Call a plumber if the noise is loud and persistent, if you can’t locate the source, or if it appears to come from inaccessible piping or built-in systems.
- Also call if you see leaks, pressure fluctuations at other fixtures, or if tightening visible clips doesn’t reduce the bang. A pro can isolate the line, test pressure, and install a water-hammer arrestor or replace a faulty valve safely.
Safety Notes
- Do not cut or disconnect water lines while they are pressurized. Shut off the appliance water supply at the shutoff valve before any work.
- Turn the appliance off and unplug it before attempting any access behind panels, and avoid confined spaces where you could become trapped.
- If you’re unsure where the sound comes from or if work requires entering walls or under-floor spaces, hire a professional to avoid injury or damage.
Common Homeowner Questions
- Why does the noise only start lately? Small changes in valve wear, water pressure, or a loosened pipe clamp can make a noise suddenly noticeable.
- Will a pressure reducer help? Sometimes reducing house water pressure or adding an arrestor stops pressure spikes, but a plumber should assess before making changes.
- Can I ignore it if nothing leaks? Occasional minor knocks may be harmless, but recurring or worsening hammering should be checked to avoid long-term pipe damage.
For more related articles, see the Noises Only When Appliances Run hub.