Look at the pressure regulator to find where it is leaking. It might be leaking from a small hole in the side, or from the threaded connection where it is connected to the other devices, such as a timer or back-flow prevention device. Or it may leak from a crack in the side.
Place your finger over the small hole in the side of the pressure regulator if the water is leaking from there. Hold it in place for five seconds and release and repeat. This helps adjust the seals inside the regulator. If water continues to leak from the hole, or if the water is pouring instead of dripping from the hole when the pressure regulator is first installed, the regulator is defective and should be returned to the manufacturer.
Look at the threaded area where it is connected to the other devices. If it is leaking from there, tighten the pressure regulator by hand until it is no longer leaking. Do not use a tool to tighten the regulator. You may damage it from over tightening. If it continues to leak from the threaded area, remove the regulator and place plumber's tape around the male threads on the regulator as well as the device where it is connected. Replace the regulator and tighten again by hand.
Return the pressure regulator to the manufacturer if the water is leaking from a crack in the device. If the crack occurred because of over-tightening, remove the damaged device and replace with a new pressure regulator.