Outside faucets are called spigots or hose bibs. In warmer climates, they are screwed to the outside pipes, which are usually made of galvanized steel. The most difficult part of unscrewing a spigot is breaking the thread seal, which is probably locked because of corrosion. In freezing climates, spigots are often soldered to the copper supply lines inside the house. These can be removed by cutting the pipe connection and then soldering on a cap to seal the water line.
Unscrewing From Galvanized Pipe
Turn off the water to the faucet. This will this prevent water gushing from the pipe when you loosen the faucet and will make the faucet easier to turn by relieving the water pressure.
Hold the pipe securely with a pipe wrench and use another pipe wrench to turn the faucet counterclockwise. Keep the wrench handle turning the faucet closer to you so that if the faucet breaks loose, you don't pinch your hand between the wrench handles.
Spray lubricant into the threads of the faucet if you can't turn it with reasonable force. Let the lubricant work for five minutes, then tap the connection with a hammer to loosen the threads and try unscrewing it again.
Heat the faucet joint with a torch to melt grime and debris locking the threads, then fit a length of pipe onto the handle of the wrench to lengthen it. Hold the pipe as close to the end as possible as you apply pressure.
Fit another length of pipe around the other wrench handle and, as a last resort, enlist the help of a friend to hold it while you use both hands to apply pressure to the first pipe.
Disconnecting from Copper Pipes
Shut off the water to the faucet, then open it to relieve water pressure. Locate the pipe inside the house that supplies the faucet.
Cut through the pipe that supplies the faucet with a pipe cutter and separate the pipes. Clean the end of the pipe that stubs out from the water supply, then spread flux on it and on the inside of a copper pipe cap. Seat the cap on the pipe, and then solder them together with a torch and lead-free solder.
Unscrew the faucet from the side of the house with a screwdriver, then pull it out. Cover the hole if you are not going to replace the faucet.