The City of Grants Pass, Oregon, has operated a medium pressure ultraviolet (UV) disinfection system for approximately 2 years. It is one of the first open channel, electronic ballast systems installed in North America. Data from the operation of the facility are evaluated to determine performance, effectiveness, permit compliance, power consumption, lamp life, labor requirements, and related operating costs. This information is anticipated to be useful to engineers and plant operators considering alternatives to the use of chlorine for disinfection. Initial operating problems at the installation and their resolution are also discussed.