The aim of the project is the use of geothermal water for district heating and reclamation of drinking water. The thermal water is produced by a former gas exploration borehole which has been equipped for geothermal water production. The heat requirements are 17 MW with an annual energy amount of 48.300 MWh. The supplied areas are residential areas, recreation areas, a hospital, different schools etc.. For the geothermal heat production, about 552,000 m3 geothermal water, cooled down from 65 deg. C to 17...23 deg. C will be used. The cooling process includes primary heat exchange and cooling work by a heat pump. By using an two step-absorption heat pump with water-lithiumbromide, the energetic results are as follows : used geothermal energy : 24,650 MWH/Y at a maximal flow rate of : 24 kg/s and a fluid temperature of : 65°C The use of absorption heat pump is technically feasible. For an high heating efficiency, the heat pump is designed for two-step-operation. In the annual average the efficiency is about 1.70 to 1.00. In peak times the efficiency rises up to about 2.2 to 1. Compared to conventional supply with use of fossil fuels, an amount of 28,999 MWh/y of fossil energy or 51% will be substituted by the energetical use of the thermal water. In the next few years, the extracted thermal water (552000 m?/y) will be used as drinking water. In future it will be used as drinking water and as thermal bathing water. The purification of the thermal water will be done by a degassing-plant and a following two-step ozoning and filtration process. The purified thermal water will be mixed with other drinking water in a proportion of max.66.7 to 100 (max.40% share) and fed into the drinking water supply of Erding.