A wearable or portable intermittently operable hydration system (10) includes a purification module (22, 50) that contains one or more solid state UV devices that are positioned in the path of hydrating fluid, or water, flow through the hydration system to a mouthpiece (18). The UV LEDs are instant on devices with essentially no ramp-up required, and a sensor (20) or the opening of a push-pull valve (53) controls the turning on of the UV LEDs. The fluid flow path may run from a bladder (12) in a backpack (19) worn by the user, a sports bottle (54) 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, power converted from pumping or winding action or any combination thereof.