Bring these

• Flashlight
• Inspection mirror
• Phone or camera

1. 1Record the timingNote the fixture, whether the sound happens on opening or closing and whether adjacent rooms hear it. Record a normal-use event if it can be done without disrupting occupants.
2. 2Compare recent changesAsk about replacement flush valves, irrigation work, pressure-reducing valve service or a recent water outage. Share this history with the plumber.
3. 3Look for visible movementObserve only exposed accessible piping from a safe position. Report missing hangers, rubbing or leaks. Do not reach into moving equipment or remove ceilings without an access assessment.
4. 4Separate local from building-wideOne fixture suggests a local review; bangs across several wings call for system investigation. Avoid repeatedly operating a fixture merely to hear the noise.
5. 5Request a measured diagnosisHave a plumber evaluate pressure, valve closing behavior, supports and appropriate arrestor location. Choose any replacement device from the resulting specification, not noise alone.

Record the exact location, observed condition, time, actions taken, person contacted and follow-up owner. Keep unresolved items visible. A completed checklist means the check was performed; it does not automatically mean the equipment passed or is safe.