Leaks in copper pipes can be troublesome. To repair a water line with copper fittings, you have to have reasonable soldering skills or your repair may not be watertight. Even if you have the skills, though, soldering isn’t easy if you can’t completely turn off the water. The solution is to adapt the line to PVC plastic. You have to connect adapters to the copper line, which involves a minimal amount of soldering, but you can make the final connections by gluing PVC, which is a much less difficult — almost foolproof — way to seal the line.
Turn off the valve that controls the damaged copper water line.