A wearable or portable intermittently operable hydration system includes a purification module that contains one or more solid state light emitting devices that are positioned in the path of hydrating fluid, or water, flow through the hydration system to a mouthpiece. The light emitting devices illuminate a photocatalytic material disposed within the flow path in order to react and create fluid-purifying hydroxyls. The lights are instant on devices with essentially no ramp-up required, and a sensor or the opening of a push-pull valve controls the turning on of the lights. The fluid flow path may run from a bladder in a backpack worn by the user, a sports bottle worn by or carried by the user or may be through a water filtration system that a user operates via a pump. The power for the purification module may come from batteries, solar cells, fuel cells, or power converted from pumping, winding, etc.