The biggest challenge when running a water line to your refrigerator is tapping into the cold water pipe and running the 1/4-in. O.D. (outside diameter) flexible copper tubing. You can buy icemaker installation kits at home centers and some hardware stores, but we don't recommend them. Most contain a saddle valve (which doesn't meet plumbing code in some regions) and some contain plastic tubing (which can dry, split and leak over time). We recommend more permanent valves and copper tubing for better water flow and reduced risk of leaks, which can cause extensive damage.
To start, locate the cold water source nearest to the refrigerator—perhaps under the kitchen sink, below the floor, in the wall or even in the ceiling. In this kitchen, we ran the new water line from under the kitchen sink through cabinets. (Note: We removed the drainpipes to clearly show this project.) Be sure to keep the tubing above storage areas and behind drawers if possible to avoid tube damage. If you need to drill through floors or walls, check for air ducts, electrical wiring, plumbing or other possible impediments first. Next, calculate how many feet of 1/4-in. O.D. flexible copper tubing you need. Figure 6 to 8 ft. of extra coiled tubing behind the fridge so you can pull it out for cleaning and service.
Then decide which one of three water line connection options you will use: a regular tee fitting that is soldered, a compression tee fitting or a saddle valve. Plumbers recommend removing a section of the cold water pipe to solder in a regular 1/2-in. copper tee. If you have CPVC (plastic) or steel pipes, add tee fittings made of the same material. If you don't want to solder, you can cut the copper water pipe and install a 5/8-in.O.D. compression tee instead (just don't use them inside walls because it's not safe and plumbing code won't allow it). Add pipe compound to the threads to make it easier to tighten compression joints.
The least dependable option is a saddle valve designed for 1/2-in. copper pipe. It has a tiny shutoff valve that uses a sharp pointed metal rod to pierce the outer wall of the pipe when screwed inward. Then you back out the rod and water flows through a tiny hole into the tubing. Some appliance installers say saddle valves work, but most refrigerator makers recommend that you drill a hole in the pipe for better flow instead of using the valve to pierce the hole, then attach the saddle valve (check your owner's manual).
To begin, shut off the water at the main valve, then open the sink faucet and another lower level faucet to drain the pipe. Next, cut out a small section of the cold water pipe and solder in a copper tee. Cut a 3- to 4-in. piece of copper pipe and solder it into the tee under the sink, then solder a water supply stop valve on the other end. Once the assembly has cooled, close the new valve and open the water main to check the fittings for leaks.
Then plan a tubing route through all the cabinets (avoiding sharp turns that can kink tubing) and drill 1/2-in. holes as needed between cabinets. To straighten coiled tubing (not the entire roll), have a partner hold the end of the tube flat on the floor, then push the roll against the floor while unrolling to the length you need to go through the cabinets. Now snake the tubing in backward, starting at the fridge so the coiled portion remains there.
Next, attach the 1/4-in. water line to the stop valve with a compression joint. Then attach the tubing to the back of the cabinets every 2 to 4 ft. using 1/4-in. nylon wire/cable clamps. Once you're outside the last cabinet, don't attach any clamps; just run the tubing to the floor near the water hookup on the fridge. But do clamp the tubing to the fridge.
Don't forget to flush out the tubing by running a gallon of water through the new line into a bucket before you attach it to the fridge. To attach the tubing to the refrigerator, follow the owner's manual.
Normally the compression fittings come with the fridge. Before you cut the tubing to its final length, make sure you have 6 to 8 ft. of coiled tubing that will remain coiled and stored behind the fridge when you push it back into place.
Be sure to cut the end of the tubing square. Then slide on the compression fittings, lubricate the threads on the refrigerator fitting with pipe compound and screw on the tubing. Important: Hand-tighten the fitting, then tighten three-quarters of a turn using a small wrench on both sides of the fitting. Once it's attached, open the new stop valve and check the entire piping system for leaks.