Step 2 · Locate the PRV
Locate the Pressure Reducing Valve (PRV) itself. It is typically installed on the main water supply line shortly after the main shut-off valve and the water meter. Look for a brass, bell-shaped device. On top of the 'bell' housing, you will find the adjustment mechanism, which is usually a long threaded bolt (the adjustment screw) secured by a hex nut (the lock nut).