Step 4 · Disconnect the Supply Line from the Shutoff Valve
To safely disconnect the line without damaging the plumbing, use two wrenches. Place one adjustable wrench on the body of the shutoff valve to hold it stationary. This prevents the valve and the pipe in the wall from twisting. Place the second adjustable wrench on the large nut connecting the supply line to the valve. Turn this nut counter-clockwise (to the left) to loosen and unscrew it. Be prepared for a small amount of water to spill into your bucket.