Originally Posted By: cradan
This post was automatically imported from our archived forum.
Most homes in urban and suburban areas are provided with water by the town. Typically, the water mains in residential areas are 4" to 12" in diameter, and run several feet below the street level. Smaller pipes, usually 1/2" or 3/4" diameter, run from city mains into individual dwellings. The water is normally supplied at a pressure of 40 to 70 psi.
-Carson Dunlap, Home Reference Book, copyright 2001, 19th ed.
I've only done just over 100 inspections, but check the static H2O pressure on virtually all of them. Public supplies range typically from about 40 to 60 or 65, I'm told some are higher (i.e. how far is your property from the nearest pumping station). Of the private supplies we've checked, pressure runs from 32 psi to 60 psi, often on the lower end of that range, i.e. @ 40 psi.
CD also suggests that when inbound pressures are known to exceed 80 psi, that a pressure regulator be installed to "prevent leaks at fixtures, stress on appliance hoses and possible broken pipe joints."
Chicago Illinois Home Inspections