A portable water treatment system for being mounted on a trailer of a truck, comprising: an input pump for pumping water from a source through the system; a filter section receiving water from the input pump; a UV treatment section for applying UV light to the water, wherein the UV treatment section comprises a tray for flow of water from an input end to an output end, wherein UV lights are disposed above the surface of the water, wherein each UV light comprises an elongated UV bulb mounted above the tray and extending substantially for a width of the tray and disposed along the length of the tray, wherein reflectors are positioned at each UV light for reflecting UV light towards the water and wherein the reflectors are mounted around each UV bulb such that the reflectors cover substantially a length and width of the tray, and wherein the UV tray further comprises multiple elongate baffles to increase water residence time in the tray, wherein each of the baffles is perforated, and wherein each of the UV bulbs are disposed above and in line with each of the baffles, respectively; and a leveling system, wherein the UV section is mounted on the leveling system, wherein the leveling system comprises a fixed frame and a movable frame, the fixed frame having one linear actuator midway along one side thereof and fixed thereto, and another linear actuator midway along another side thereof and fixed thereto, and the linear actuators (226, 228) are gimbaled at an upper end thereof to the movable frame, and bearings disposed along an intersection of axes of the gimbaled portion of the actuators (226, 228) to the movable frame and the bearings, the UV section being mounted on the movable frame, wherein the bearings are located at a center of mass of the moveable frame, and the upper end of each linear actuator (226, 228) is positioned so as to align with an axis of a respective one of the bearings, and wherein the leveling system includes a level detection mechanism comprising pendulums, each pendulum comprising a housing, a damping fluid therein, a pendulum arm for swinging freely within the housing, and detectors for detecting a position of a bottom portion of the pendulum. an input pump for pumping water from a source through the system; a filter section receiving water from the input pump; a UV treatment section for applying UV light to the water, wherein the UV treatment section comprises a tray for flow of water from an input end to an output end, wherein UV lights are disposed above the surface of the water, wherein each UV light comprises an elongated UV bulb mounted above the tray and extending substantially for a width of the tray and disposed along the length of the tray, wherein reflectors are positioned at each UV light for reflecting UV light towards the water and wherein the reflectors are mounted around each UV bulb such that the reflectors cover substantially a length and width of the tray, and wherein the UV tray further comprises multiple elongate baffles to increase water residence time in the tray, wherein each of the baffles is perforated, and wherein each of the UV bulbs are disposed above and in line with each of the baffles, respectively; and UV lights are disposed above the surface of the water, wherein each UV light comprises an elongated UV bulb mounted above the tray and extending substantially for a width of the tray and disposed along the length of the tray, wherein reflectors are positioned at each UV light for reflecting UV light towards the water and wherein the reflectors are mounted around each UV bulb such that the reflectors cover substantially a length and width of the tray, and wherein the UV tray further comprises multiple elongate baffles to increase water residence time in the tray, wherein each of the baffles is perforated, and wherein each of the UV bulbs are disposed above and in line with each of the baffles, respectively; and a leveling system, wherein the UV section is mounted on the leveling system, wherein the leveling system comprises a fixed frame and a movable frame, the fixed frame having one linear actuator midway along one side thereof and fixed thereto, and another linear actuator midway along another side thereof and fixed thereto, and the linear actuators (226, 228) are gimbaled at an upper end thereof to the movable frame, and bearings disposed along an intersection of axes of the gimbaled portion of the actuators (226, 228) to the movable frame and the bearings, the UV section being mounted on the movable frame, wherein the bearings are located at a center of mass of the moveable frame, and the upper end of each linear actuator (226, 228) is positioned so as to align with an axis of a respective one of the bearings, and wherein the leveling system includes a level detection mechanism comprising pendulums, each pendulum comprising a housing, a damping fluid therein, a pendulum arm for swinging freely within the housing, and detectors for detecting a position of a bottom portion of the pendulum.