Abstract: A hand-held water purification system includes an outwardly-extending pen-light sized configuration of solid state devices, such as, UV-light emitting diodes, that emit ultraviolet light in the germicidal range. The system operates to turn on the solid state devices under the control of one or more switches that are, in turn, under the control of a liquid-level sensor that senses when the configuration is immersed in the water. The system may also include a timing circuit that turns the solid state devices off a predetermined time after they are turned on. In one embodiment, a battery powers the various components of the system. In an alternative embodiment, the system power is provided by a base that plugs into a conventional power outlet. The base includes a converter that converts the signal provided through the power outlet to a signal that is appropriate to power the components.