The small Sterilight SQ-PA through S2Q-PA systems are ideally suited for point-of-use filtration, reverse osmosis pre or post disinfection, while the larger S5Q-PA, S8Q-PA and S12Q-PA systems can be used on a point-of-entry system, disinfecting the water for an entire home or small business. The low pressure germicidal lamps provide an economical way of treating water requiring a 99.99% reduction in bacteria and viruses. These simplistic designs allows for easy homeowner maintenance. The UV lamp can be changed without interrupting the water flow. The quartz sleeve design allows for maximum UV output and operating efficiency.