Water pressure Reducing Valves are deceptively simple devices. Typically, they involve a spring and a diaphragm connected to a pintle (a pin or bolt) that regulates water flow. The spring is adjustable and is set at the desired pressure and the diaphragm acts as an equilibrium force that readjusts the spring depending on the incoming pressure. 

Like everything mechanical, water pressure Reducing Valves can and do wear out and it is a good idea to monitor the water pressure within a home to ensure everything is ship-shape. Not all homes are equipped with them, however, and it