Protection of groundwater supplies of water intended for drinking is the most important goal of any organized society. This paper presents the approach to groundwater protection in the area of Harina Zlaka. The aquifer is located in a well-permeable carbonate rock complex of Middle and Upper Triassic age. Previous research has found a large amount of drinking water suitable for human consumption that is affected by two wells. Based on geological, structural and hydro-geological research and the results of determining groundwater quality indicators, a proposal of zones for sanitary protection of springs has been made according to Croatian regulation and legislation. Groundwater has thermal characteristics and it meets all the criteria necessary for water intended for human consumption in a physical, physicochemical, toxicological, radiological and microbiological aspect. Restrictions have been proposed for each zone as well as active and passive remedial measures for the purpose of their protection. Groundwater protection improvement in the spring basin can be achieved by building a wastewater drainage system for some parts of Harina Zlaka. Prior to entering the Sutla River, water has to be purified to a level that will not endanger the river's ecosystem. The future of using groundwater from the Harina Zlaka pumping station with the proposed protection will enable a long-term drinking water supply for the whole area. Also, thermal characteristics of the underground water open up the possibility of further research of thermal water with higher temperature which can be used as a renewable energy potential, as well as for tourist and recreational purposes.