How to Install a Faucet for an Undermount Kitchen Granite Sink

Locate the two plumbing connections, one for hot water and the other for cold, which you will connect to your faucets. Place a strip of Teflon pipe tape around the threads of each of the connectors to help in making the connection watertight between the household plumbing connectors and the faucet water connectors. Wrap the tape counterclockwise around the threads, using four or five revolutions around the threads and molding the tape tightly to the thread surface. Leave the shape of the threads intact so that you can still screw on the faucet connectors.

Place the O-ring for the faucet over the bottom of the water feeder lines and push upwards as far as possible onto the faucet base. Lower the feeder lines through the hole in the countertop until the faucet base is flush with the counter surface.

Slide the mounting washer over the feeder lines from beneath the sink and over the base of the faucet, followed by the flange nut. Tighten the nut over the base of the faucet finger-tight to hold the faucet in place. Tighten the nut further with a wrench until the faucet does not move on top of the counter.

Connect the supply line to the faucet, tightening the line nut over the Teflon-coated threads. Connect the other end of the line to the Teflon-coated threads of the house plumbing lines. Make certain you connect the hot water to the hot water supply for the faucet and the cold to the cold water supply to avoid accidental scalding with faucet use. Tighten the supply hoses in place with a wrench.

Test the connection by turning on the water supply slowly and watching for leaks. Turn the water off if you have a leak, and reconnect the leaky connection to make certain the connection is tight. Turn the water on fully when no leaks occur.

Apply a bead of silicone caulking around the base of the faucet. Smooth the caulk into place with your finger. The caulk will prevent water from leaking from your countertop to the cabinet beneath through the joint at the base of the installed faucet.