This is a record of the decision for proposed construction of additional wastewater treatment facilities at Jackson Hole, within Teton County, Wyoming. The U.S. Environmental Protection Agency (EPA), Region VIII, is authorized to grant 75 percent matching funds for construction costs of designated wastewater treatment facilities. Sewage discharges as a result of area growth and development together with non-point source runoff have degraded the water quality of Flat Creek. Therefore, additional sewage treatment facilities are needed to meet water quality goals. The approved action is to construct aerated lagoons followed by rapid infiltration basins 4 miles downstream of the existing plant. The new facility will enhance development in the undeveloped South Park area. Groundwater monitoring will be required.