Over the past 2 decades, numerous man-made ponds and lakes constructed in country clubs and on golf courses in the Coachella Valley have become ideal habitats for various chironomid species. Large numbers of adult midges emerging from these water bodies pose nuisance and economic problems. During 1992 and 1993 we initiated comprehensive studies on the nature and scope of the nuisance midge problem in the valley. We sampled on a biweekly basis 2 lakes supplied with well water, 2 supplied with tertiary effluent water, and one supplied with a mixture of these 2 sources, to determine the midge larval fauna and the mode of existence, seasonal abundance, and population trends of these midges. Climbers, clingers, portable sand tube builders, and tube builders on plants predominated in well-water habitats with submerged vegetation and detritus bottoms. Tube builders and burrowers predominated in the tertiary water, which characteristically had a detritus bottom, devoid of vegetation. Habitats holding a mixture of the 2 water types with sandy bottoms supported midge larvae known to be sprawlers.