In this video, This Old House plumbing and heating expert Richard Trethewey taps into a water-supply line.
1. If necessary, drill a ⅝-inch-diameter hole through the floor directly behind the refrigerator.
2. Turn off the water to a nearby cold-water supply line.
3. Use a strip of emery cloth to buff-clean a section of the copper water line.
4. Cut into the cold-water line using a tubing cutter.
5. Brush flux onto a ½-inch copper transition fitting and onto the pipe end.
6. Push the fitting onto the pipe, then heat the fitting with a propane torch.
7. When the flux starts to bubble, solder the fitting onto the pipe.
8. Wrap Teflon tape around the threads of a ¼-in. compression tubing connector.
9. Thread the connector into the transition fitting; tighten the connector with pliers and an adjustable wrench.
10. Take the flexible water-supply tubing from the back of the refrigerator and feed it down through the hole in the floor.
11. Brush pipe dope onto the cone-shaped ground joint connection.
12. Thread the nut on the tubing end onto the compression connector soldered to the cold-water supply line. Tighten the nut with pliers and an adjustable wrench.
13. Turn the water back on and test the water dispenser in the refrigerator door.