Step 2 · Disconnect Water Supply Line
Locate the water supply line, which is the flexible hose connecting the shut-off valve to the bottom of the toilet tank. Place an old towel or a small bowl directly underneath the connection point at the tank to catch any trapped water. Using an adjustable wrench or channel-lock pliers, grip the coupling nut on the supply line where it threads onto the fill valve shank. Turn the nut counter-clockwise to loosen and unscrew it completely. Let any remaining water drain out onto the towel.