This report provides instruction for evaluating sprinkler system distribution using the superimposed method. Coefficient of Uniformity is the term used to evaluate how evenly water is distributed from sprinklers. Small cans are placed within a square (or grid) of 4 sprinklers, or within the triangle of 3 sprinklers, depending on whether a square or triangle spacing of sprinklers is used, and the amount of water collected in each can is used to calculate the coefficient of uniformity. The cans are placed on a 10 foot grid, one at each corner of the 10 ft. grid, or one in the center of each grid.