Garbage disposal makes a rattling noise only when water is running, even if the unit is off.

Safety first: Turn off power to the disposal before reaching into the sink opening or adjusting mounting hardware.

• Step 1 – Check splash guard: Press down on the rubber baffle while running water. If the noise changes or stops, the guard may be loose; reseat or replace it.
• Step 2 – Inspect mounting ring: From under the sink, tighten the mounting ring and any associated screws.
• Step 3 – Adjust discharge piping: Ensure the discharge elbow and drain pipes are not pressing against the cabinet or disposal body. Add pipe supports or padding if needed.
• Step 4 – Test: Run water again and confirm the rattling has stopped.