Gio,

I would say you need to install the pressure regulator as close to the house as possible (it usually goes in the garage with a shut off valve next to it) and leave the sprinkler connection (if it is from the main house line) between the regulator and the street. Check your outside faucet (house) pressure with a pressure tester that connects to the faucet from the hardware store. The pressure should be at 45 to 55 psi. If not, then turn the nob on the regulator adjustment screw to achieve that range. Aloha