Step 5 · Install Water Supply Lines
First, SHUT OFF THE MAIN WATER SUPPLY to the house and open a nearby faucet to relieve pressure. Locate the nearest 1/2-inch hot and cold water lines. Assuming they are PEX, use a PEX cutter for a clean, square cut. Insert a 1/2-inch PEX tee fitting into each line. Slide a copper crimp ring over the pipe, push the fitting fully into place, and use a PEX crimping tool to secure the ring. Repeat for all three ends of both tees. From the open ends of the tees, run new lines of 1/2-inch red PEX (for hot) and blue PEX (for cold) up through the wall to the outlet box opening. Leave several inches of extra pipe extending into the opening.