"Understanding Your Home" by Building Inspector Mark Visser
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High water pressure. PRV.
Pressure Relieve Valve.
Pressure reducing valve.
Pressure regulating valve.

If you suspect that the water pressure is too high you can check the static water pressure by threading a water pressure gauge onto any hose bib and turn on the water. The static water pressure is the pressure, anywhere, on the water supply system while all other fixtures are turned off. If the home is on a well and pump system, let the water run till the pump starts running. If the pressure is 80 psi or more you have to install a PVR.
The standard, set by plumbing codes in many jurisdictions, is 60 psi.

To get an accurate reading
make sure that the hose bib is
not leaking and that all other
fixtures, including sprinklers
and washing machine,
are turned off

High Water Pressure
how to fix it

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High water pressure. PRV. Pressure Relieve Valve. Pressure reducing valve. Pressure regulating valve.
In an earlier article we discussed low water pressure issues but the opposite, high water pressure, can be a problem as well. The good news about high water pressure is that it is a lot easier and cheaper to fix than low water pressure. Water pressure is measured in psi (pound [force] per square inch)

There are some tell-tale warning signs of high water pressure that you should be aware of.
- There is a real burst of water when you turn on the water at any faucet in the house.
- Water hammer when you turn off a faucet, or when the dishwasher or washing machine stops using water. Water hammer can damage soldered joints and cause leaks.
- The plumbing throughout the house seems to be noisy.
- Higher than normal water bills because,
- toilets keep running, dishwasher start filling when not in use, faucets seem to be dripping "forever"
- premature wear of faucets and appliances.
Take immediate steps to reduce high water pressure when the PRV (Pressure Relief Valve) on the water heater is leaking.

Pressure relief valve for jet and submersible well pump systems
pre-set at 75 psi

On a well system, the normal pressure is 20 to 60 psi, city water pressure varies but in many municipalities it is 50 to 75 psi.
Most experts agree that water pressure should never be more than 80 psi. If the water pressure is more than 80 psi you may experience some of the problems listed above. Recently I contacted the Public Works, Water Distribution Department and asked them for water pressure used in my city and this is their reply "The Region supplies water in the range of 40-80 psi. It does get up as high as 100 psi, but that is unusual." However, when I checked the pressure at the hose bib I found that the water pressure was only 35 psi.
Most everything in plumbing that requires water pressure to operate was engineered for 60 psi.

PRV (Presure Relieve Valve)
Adjustable PRV
A water pressure relieve (or regulating, or reducing) valve is a device that uses a spring and adjustable diaphragm to reduce the home's water pressure to a preferred psi. A PRV automatically reduces the high incoming water pressure from the watermains to provide a lower, more functional and save water pressure for distribution throughout the home
The PRV opens or closes down the total flow through the valve in response to varying GPM (gallons per minute) drawn in the house. The result is that the pressure in the plumbing supply system remains more or less the same. The valves are set by the manufacturer at lets say 50 psi but can be adjusted anywhere from 25 to 75 psi. These figures may vary depending on the manufacturer of the PRV.
Pressure reduction valves are fairly common in areas where water pressure is constantly more than 80 psi.
The best place to install the PRV is on the house side of the water meter. Pressure reducing valves come in multiple sizes. Look for a PRV with a range of 40 psi (or lower) through 70 or 80 psi. You have the option of in creasing or decreasing the water pressure by simply adjusting the screw or hex head nut at the top of the valve. The PRV should be installed by a certified plumber.
Pre-set none adjustable PRV
The pressure relieve valve shown above is for jet and submersible well pump systems. The valve cannot be adjusted and is pre-set at 75 psi to protect the system from excessive pressure build-up.

If the water pressure is 80 psi or more a PRV should be installed to prevent problems as listed above, see "TELL-TALE SIGNS OF HIGH WATER PRESSURE" above.

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