Assessment of potential use of ground-coupled heat pump (GCHP) system in regional scale is important to promote its growth. Groundwater flow system and subsurface temperature distribution of Tsugaru Plain were comprehended by developing 3D numerical model. In absence of measured hydrological and temperature data, analysis model was verified by constructing single ground heat exchanger models and incorporating thermal response test results. Prepared distribution maps of effective thermal conductivity and subsurface temperature are significant for proper siting of GCHP system. Potential map developed for space-heating purpose can assist for optimum design and economic feasibility of the system. Potential ranking used in the potential map was mainly based on effective thermal conductivities and subsurface temperatures. (C) 2014 Elsevier Ltd. All rights reserved.