During the first three months of this one-year study to determine the technical, economic and environmental feasibility of heating the town of Mammoth Lakes, California using geothermal energy, the following work was completed. Literature concerning both geothermal and conventional hydronic heating systems was reviewed and put on file. Estimates were prepared for the monthly electrical energy consumption and peak electrical demand for space and water heating in Mammoth Lakes Village in 1980. An analysis of the energy potential of the Casa Diablo geothermal reservoir was completed. Discussions were held with US Forest Service and Mammoth County Water District employees, to obtain their input to the feasibility study.