Tritium in the heavy water systems of Ontario Hydro's Nuclear Generating Stations presents a radiological hazard both to station personnel and to the environment. Careful design of equipment, containment and the use of personal protective equipment reduces but does not remove the hazard. To deal more effectively with the problem, Ontario Hydro plans to remove the tritium in a new facility currently under construction. Accordingly, the management of tritium, by the selective use of the tritium removal facility, will play an important role in reducing the tritium hazards at the stations. This paper describes the models and management techniques used.