: I would like to know what causes water pipe hammering and how I would go about correcting it?
Water flows under pressure quickly through the pipes when you open a faucet, and stops suddenly when you close it. As it rushes around bends it has its own inertia. Each action has its own reaction. Plumbers are required to fasten the piping securely to hangers or framing members when new construction occurs. The constant vibration transmitted to those fasteners sometimes causes them to wiggle loose inside the wall cavity, and then the pipe vibrates against the framing members or against other utilities inside the wall. To correst it, pinpoint the vibration noise location. Cut open the drywall, resecure the pipe to the framing member and or cushion the nearness to other utilities, and replace the drywall and paint.