Step 2 · Locate the PRV and Loosen the Lock Nut
Locate the water pressure reducing valve. It is usually a brass, bell-shaped device installed on the main water line shortly after the main shutoff valve and water meter, often in a basement, crawlspace, or utility room. Identify the adjustment screw on top of the 'bell' and the lock nut that holds it in place. Using an adjustable wrench, turn the lock nut counter-clockwise about a half to a full turn to loosen it. This will allow the adjustment screw to be turned.