When you discover a leak, you should immediately learn how to you can temporarily stop the leak until you are able to call a professional. Stopping a leak right when you find it can save you from more water damage and helps replacing the pipe a much easier process.
Here is a step by step plan to help you until a professional can come fix it:
1.) Turn the water supply off and then eliminate all forms of condensation and remaining water by wiping the pipe dry with a towel or cloth and leaving it to air dry before address the leaking area.
2.) Apply epoxy putty to fully cover the surface around the leak and wait until it is fully cured.
3.) Turn on the water and check for leaks.
Once you are finished, call your local plumber to help make it a permanent fix!