With all the water turned off, the water pressure meter measures 140psi. When I turn on one faucet, the meter drops to 40 psi. Do I have a problem?

140 PS I is over three times the average house average of 45 PSI. Too much pressure can damagefittings and valves. How old is your house and what material are the pipes? Do you have a pressure reducing valve installed where the water enters the house? Answer me back and I'll get right back to you. Regards, Tom

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Originally Posted by speedball1

140 PS I is over three times the average house average of 45 PSI. Too much pressure can damagefittings and valves. How old is your house and what material are the pipes? Do you have a pressure reducing valve installed where the water enters the house? Answer me back and I'll get right back to you. Regards, Tom

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There is a PRV in the mechanical room before the water enters the house copper pipe system. The house and its plumbing are 17 years old.

Is a rating of 140 PSI taken before the PRV valve or after it enters the house? Back to you, Tom

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Originally Posted by speedball1

Is a rating of 140 PSI taken before the PRV valve or after it enters the house? Back to you, Tom

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140 PSI is taken after the PRV valve on a faucet after it enters the house

The mystery deepens! You lose 100 PSI in your house pressure when you open a cold water faucet? And this is throughout the entire house? Is sounds like something is constricting the flow in your pipes. When the hundred and 40 PSI hits the blockage it restricts the volume and when the volume is restricted the PSI falls off. If the entire house is affected then the restriction has to be close to the entry point. Have you any thoughts on this? Regards, Tom