Tauranga, on the north coast of the North Island of New Zealand, is the site of a fairly extensive low-temperature (60˚C at 800 m) geothermal resource that is currently used for hot pools, swimming baths, domestic use, greenhouses and tropical fish growing. As the population of the area grows and interest in direct use of geothermal resources increases, the system comes under increasing demand. In this study, a TOUGH2 heat and fluid flow model of the Tauranga geothermal field is used to determine the extent of the system, and the possible effects of withdrawing hot fluid from the area