When tapping into the water heater, turn the water heater off at the breaker. If the water heater is gas, turn it to the "pilot" position.
Purge the plumbing system by opening the hot water side of the lowest faucet in the home.
Cut into the water heater's cold water line with a pipe cutter, allowing the water in the pipe to drain into a bucket. Make another cut, and then remove the section of pipe.
Wearing latex gloves, clean and de-burr each end of the cut pipe. Do the same for the coupling.
Repeat these steps for a 90-degree elbow and another section of pipe. Attach the elbow followed by the pipe.
The correct valve to use for a sillcock shut-off valve will have a small hole called a petcock, which is very important for winterization. Also, the valve will have an arrow pointing in the direction of the water flow.
Once the shut-off valve is in the correct position, solder all of the joints.
Note Keep a rag handy to wipe off excess solder.
Close the shut-off valve, and turn the water back on.
Turn off the faucet, and check for leaks.
Turn the water heater back on.
Drill through the sill plate using a paddle bit. Start with a small hole from the inside of the wall to prevent running into other pipes or wires -- then drill a larger hole from the outside (Image 1).
Note: When drilling through masonry block, drill into the center and move the drill around to open up the hole. For brick, drill into the mortar (Image 2).
When installing a frost-proof sillcock, bore the hole at a slight angle to the ground. This will allow the sillcock to lean towards the ground, helping to drain the area.
Open up the sillcock to prevent the heat from soldering to build up.
Clean a couple of smaller sections of copper pipe, as well as a 90-degree elbow. Apply flux, and then slip the pipe into the elbow.
Solder the connection, and then mount the unit to the sillcock.
Measure the distance between the sillcock and the water line with a piece of cut pipe.
Cut the excess using a pipe cutter.
Clean and prepare the connecting pipe, 90-degree elbows and any exposed pipes.
Slide the elbows on either end, and then connect the sillcock to the water line (Image 1).
Solder all of the joints (Image 2).
Open the shut-off valve, and then allow the outside sillcock enough time to flush out debris before turning it off.