Water pressure regulator

Between 50 and 65 psi static, measured with all fixtures off. The plumbing code allows up to 80 psi at fixtures but that is a maximum, not a goal. Below 40 psi feels weak at showers and when two fixtures run at once; above 80 psi is out of code and shortens the life of every valve, hose and appliance in the house.

Buy a brass hose-thread pressure gauge for about $12, thread it onto the exterior hose bib nearest where water enters the house, turn everything else off, and open the bib fully. That gives you static pressure. Then leave the gauge on overnight with the maximum-reading needle set. Night-time municipal rise and thermal expansion spikes are invisible during the day and are often the real problem.

It is a bell- or cone-shaped brass valve, usually four to six inches long with an adjustment screw and locking nut on top, fitted on the main line just after the main shutoff. Look where the water enters the house: a basement wall, a utility closet, a garage, a crawl space, or occasionally in the meter pit at the kerb. Many houses on lower-pressure streets have none at all, which is legitimate if street pressure is under 80 psi.

Ten to fifteen years is the usual working life, sometimes less in areas with sediment or aggressive water chemistry. They are wearing parts with a rubber diaphragm and a spring, and they fail gradually. If yours has an install date on it and that date is more than fifteen years ago, budget for it whether or not it is misbehaving yet.

On a healthy valve, yes, carefully: loosen the lock nut, turn the adjustment screw clockwise for more pressure and anticlockwise for less, a half turn at a time, with a gauge fitted and a tap briefly run between adjustments so the reading settles. Retighten the lock nut when finished. If the gauge does not respond, stop. The valve has failed internally and turning the screw further will not help.

Most often thermal expansion in a closed system. Once a regulator is fitted, heated water cannot expand back toward the street, so pressure spikes each time the heater fires and the relief valve does its job. The fix is a thermal expansion tank sized for the heater, not a new relief valve, though a valve that has discharged repeatedly often needs replacing too because it stops reseating cleanly.

Possibly, but check the pipe first. A regulator can fail closed or clog at its strainer, which produces gradual whole-house pressure loss. But in houses built before 1960, low pressure is far more often galvanised steel supply pipe that has closed up with internal rust. Test at the hose bib nearest the meter: if the pressure is fine there and poor inside, the problem is the pipe, not the valve.

A pressure reducing valve is required where the static street pressure exceeds 80 psi, which covers a great many Virginia neighbourhoods. Replacement is permitted work in most localities. If your street pressure is comfortably under 80, no regulator is required, though many owners fit one anyway to hold a steady 55 psi.

Yes, measurably. Flow through any opening increases with pressure, so identical behaviour at 100 psi uses noticeably more water than at 55 psi. Every shower, every tap, every flush. Reducing pressure to a sensible range is one of the few plumbing changes that pays for itself on the utility bill as well as in fixture life.

Yes, if there is a storage water heater in the house. The regulator closes the system, the closed system needs somewhere for heated water to expand, and the expansion tank provides it. Fitting the regulator alone commonly produces relief-valve dripping and pressure spikes within weeks. The two together are one visit and one set of connections.