Knocking Pipes.

Water is heavy and when turned on and back off it's weight tries to move the pipes. Typically the knocking is a loose pipe banging against the inside of a wall, floor or ceiling.

If pipes are accessible through an unfinished room or basement they can be inspected while someone else turns on and off the offending faucet or appliance. It could be as simple as an addtional bracket to hold the pipe or a cushion against a stud or joist.

The water itself, within the pipes can also cause the banging sound. Anti-knock air chambers can be built into plumbing systems. Air can be compressed, water cannot be compressed so
the air pocket cushions the blow. If the air chambers fill with water over time, the cushioning effect is lost.

Draining the plumbing system of water allowing it to fill with air before refilling can restore air to the anti-knock chambers.

Noisy plumbing can become more noticable if the water pressure is too high. If your water pressure is higher than 45-50 psi a water restrictor should be used.

If the noise seems to be coming from within the toilet, check for worn out washers and seals in the refill valve.

Knocking Pipes.

Water is heavy and when turned on and back off it's weight tries to move the pipes. Typically the knocking is a loose pipe banging against the inside of a wall, floor or ceiling.

If pipes are accessible through an unfinished room or basement they can be inspected while someone else turns on and off the offending faucet or appliance. It could be as simple as an addtional bracket to hold the pipe or a cushion against a stud or joist.

The water itself, within the pipes can also cause the banging sound. Anti-knock air chambers can be built into plumbing systems. Air can be compressed, water cannot be compressed so
the air pocket cushions the blow. If the air chambers fill with water over time, the cushioning effect is lost.

Draining the plumbing system of water allowing it to fill with air before refilling can restore air to the anti-knock chambers.

Noisy plumbing can become more noticable if the water pressure is too high. If your water pressure is higher than 45-50 psi a water restrictor should be used.

If the noise seems to be coming from within the toilet, check for worn out washers and seals in the refill valve.