Because most of our water service areas are not flat most water systems have multiple water pressure zones. A water pressure zone is a geographic section of a water distribution network that is determined by the elevation of the area served.
The pressure in the water system, known as hydraulic pressure, is created by gravity pulling a column of water downwards. At an average height of about 120 feet, water towers properly pressurize the water distribution pipes within a pressure zone.
Within a pressure zone, a minimum pressure is established by pumping stations or reservoirs. Water does not flow between pressure zones unless it flows from a higher pressure zone to a lower pressure zone, through a pressure reducing valve. Water pressure in a pressure zone typically ranges from 40 to 130 psi, but may be higher.