Replace the pressure regulator and add the expansion tank. You should also consider hammer arrestors at the washer, dishwasher and the icemaker. Terry

: I just replaced the pressure relief valve on the hot water heater as it was running continuously. I also purchased an expansion tank but haven't installed yet. Water pressure is high. I have 112 PSI water pressure on the house water and have a pressure regulator rated 20-75 PSI. Is this proper operation (when I open a faucet....the pressure drops - but on closing the valve - pressure always returns to 112PSI)

: I looked at a NEW pressure regulator at Lowe's and it said if water pressure is over 150PSI at the street - to get an expansion tank. I don't know what the street pressure is - but I cannot change the home pressure through the full range of adjustment on the pressure regulator (again - it always returns to 112 PSI after opening and closing a faucet)

: My guess is the regulator is bad???