The occurrence of geothermal resources in Poland relates to four main hydrogeothermal provinces: the Polish Lowlands, the Carpathians, the Carpathian Foredeep and the Sudetes, each characterized by different geological conditions. Recognition of Poland’s geothermal potential on a regional scale is good, yet, in order to evaluate the capabilities of utilising geothermal waters taking into account specific local conditions, a detailed geological, hydrogeological and thermal analysis is required in each case. Sometimes, the results of this analysis provide new insights into the geological structure and hydrogeological conditions in the region of specific resources, and indicate alternative approaches to resource evaluation. We summarise the geological conditions around geothermal water resources in Poland, and also illustrate local variability in selected hydrogeothermal parameters in the area of Wiśniowa, located in the Outer Carpathians, and in Poddebice, a central part of the Polish Lowlands. Selected examples of the effects of the research carried out in these areas of Wiśniowa and Poddebice show situations where the results of making a borehole can be unpredictable.