Provided herein are systems and methods for the treatment and purification of fluids (e.g., water) using a light-emitting diode (LED) light source. In one embodiment, for example, there is provided a fluid flow conduit having an LED light source and a photo-catalytic material disposed therein. The LED light source emits ultraviolet light with a peak wavelength between about 265 nm and about 400 nm. In operation, the photo-catalytic material absorbs the ultraviolet light from the LED light source, and releases free radicals into the fluid. The free radicals then degrade organic substances (e.g., bacteria) in the fluid.