Water hammer or hydraulic shock is often caused by a lack of air chambers. When a valve is shut off quickly (washing machines and dishwashers, for example, can turn off the water very fast) The air in the chamber will compress, absorbing the shock that would normally be passed down the pipe. These air chambers typically consist of a short segment of vertical pipe near the valve which is capped.
These chambers can get saturated with water and they can quit working, resulting in noisy operation. Water hammer is normally associated with metal plumbing but can also happen with plastic supply lines. This may be a cause of movement and flexing which could damage plastic pipes. You may be able to correct the problem by recharging these air chambers in your plumbing system.
Step 1 – turn off the main water to the home
Step 2 – Open all of the plumbing fixtures in the home, particularly the highest and lowest faucets.
Step 3 – When all the water has drained, air will enter the supply lines and recharge your air chambers
Step 4 – Once the water has finished draining, turn off all of the valves and then turn the water main back on to the home.
These simple steps can be effective in helping to keep your supply plumbing quiet and trouble-free.