The drinking water line had a bang every time the tap was closed quickly. The easy fix is a cushion of air.
A 10” piece of ½” copper pipe was soldered and capped above the shut off valve. When the kitchen tap is suddenly closed, the air space acts like a shock absorber.
Step 1: Replenish the Air
Over time, the air is absorbed into the water and the space needs more. Upstream is the sand filter, which must be replaced every 3 or 4 months. When the new filter is put back in service, opening the drinking tap slowly will purged the air through the line and refill the space.