Locate the water pressure reducing valve on the main water line
Check the current water pressure with a pressure gauge
Turn off water to the system if needed
Loosen the locknut on the adjustment screw
Turn the adjustment screw clockwise to increase pressure
Turn the adjustment screw counterclockwise to decrease pressure
Make small adjustments, about a quarter turn at a time
Recheck the pressure after each adjustment
Tighten the locknut once the desired pressure is reached
Turn water back on and check for leaks
Call a licensed plumber if the valve does not adjust properly