Even the smallest of leaks in a copper pipe can cause water damage to your home. Whether it's simply rusting the pipe or causing rot in your basement, a pinhole leak cannot be ignored. Some basic methods will help you to seal a pinhole leak in your copper pipe until you can have a professional looking into the pipe system.
Turn off the water flow to the area of pipe that has the leak. This may require you to turn off water flow to a section of your home. However, running water may change the effectiveness of some of the materials used to seal the leak.
Isolate the pinhole leak. Remember that leaking water will run across or down pipes. Be sure that you find the actual source of the leak. In copper pipes, the area around a leak will often begin to turn blue or green due to water damage. Look for this telltale sign when isolating the leak.
Dry the area around the leak thoroughly. Wrap electrician's tape around the leak. Continue to wrap the pipe up to 6 inches from the area of the leak for a stronger seal. This seal is extremely temporary, however, as electrician's tape is not waterproof.
Use plumber's epoxy to help seal the pinhole leak. Epoxy is waterproof and will seal up the leak. Plumber's epoxy can be found at plumbing specialty or hardware stores. Tear off a small piece of the epoxy and push onto the pipe with your thumb or a putty knife; allow time to dry and seal before turning the water back on.
Purchase pipe clamps and a small piece of rubber if these other strategies have not worked. These materials are available at hardware or automotive stores. Hold the rubber in place over the leak and place a clamp on either side to hold it in place, thus blocking the leak.