Recently I had to call a plumber because my shower was leaking and I was not sure if it was an easy fix. Plumber came and replaced the cold water valve and that fixed leak however in the process he found a plastic pressure reduction device that I think was sent out by Watercare in Auckland to save water several years ago. The plumber complained that this was what had caused the leak as it forces the pressure back up to the valve. As the system was over 30 years and the reducing disk had been in place for a decade I wonder if his comments are correct. Surely the water company would not have recommended the disks if there was a chance they could damage the system. Is there anyone with experience in this area that can comment? The pressure coming out of the shower now is quite vicious and I don't really want to get an exorbitant water bill.