A computational study on UV disinfection efficiency has been developed based on the Lambert-Beer law. Comparing a UV lamp arranged vertically to the flow of one arranged on an incline led to the conclusion that UV doses could be increased. The study of the inclination effect was divided into four stages in order to evaluate the increase in the UV dose at each stage. The slope of the inclined UV lamp ranged between 1° and 89° (0°<θ<90°) with other parameters such as diameter of the UV lamp, distance from the surface of the UV lamp, and velocity also recorded. The increase of UV dosage was largely affected by the diameter and velocity of the UV lamp, especially on a lesser slope. To obtain a greater UV dose, it was necessary to assemble UV lamps with lesser slopes. By arranging lamps on an incline, UV disinfection could be enhanced.