Step 3 · Install the New Supply Line

This is the step people usually slow down on. Go finger-tight first, then a quarter turn. No rush — replay the clip whenever it helps.

Take your new Toilet Water Supply Line. First, attach the top coupling nut (typically plastic) to the threaded shank of the toilet fill valve extending from the bottom of the tank. Thread it on by hand, turning clockwise until it is snug. Ensure it is not cross-threaded. Once hand-tight, use a wrench or pliers to give it an additional quarter-turn. Do not overtighten. Next, align the bottom coupling nut (typically metal) with the threaded outlet on the shutoff valve. Thread this nut on by hand until it is snug. Then, using an adjustable wrench, tighten it another quarter to half-turn until it feels secure.