Abstract: A water purification system is disclosed comprising a reverse osmosis chamber coupled to a multi-pass ultraviolet chamber for irradiating water with ultraviolet light radiation both before and after the water passes through the reverse osmosis chamber. The multi-pass ultraviolet chamber provides a plurality of water conveying tubes in proximity to an ultraviolet light radiation source. The diameter of the conveying tubes is substantially larger than the diameter of conduits feeding the tubes. Accordingly, the water flow through the tubes decelerates, thereby increasing the duration of ultraviolet light radiation exposure to the water in the tubes. Additionally, a removable cover is located above the ultraviolet light bulb in order to facilitate easy replacement of the bulb.