Repairing a leaking cylinder does depend on the location of the leak. If it is leaking from a valve or fitting, usually this is a common repair and an easy fix, however, if it is leaking from the anode port or the tank internally, this is usually a sign that the tank may need replacement. It is important to check the age, life-span and condition of the tank as it may be more feasible in the long run to replace the tank rather than repair. If you have a solar hot water system, it may be possible to replace the tank only, and retrofit your existing solar controller, pump and collectors to the new tank rather than having to replace the complete system.