Despite safe access to drinking water being recognized by the UN as a basic human right, millions of people around the globe lack adequate supplies, with water-related diseases still being a major cause for mortality, particularly in developing countries. The aim of this study is to test a novel, low-cost solar pasteurisation technology, which has a built-in function to self-regulate according to available sunshine, in order to assess its suitability for safely processing water for drinking purposes. The device, known as a passive solar thermal pasteuriser, can be applied in environments where it is critical to pasteurise the water by reaching sufficient temperatures. A prototype was tested under laboratory conditions, with lamps calibrated to provide representative solar irradiances. Experiments under varying conditions show temperatures as high as 76°C were reached, which according to the literature is sufficient to pasteurise water in less than 5 minutes, providing safe drinking water and eliminating common waterborne pathogens. Future tests and field trials are currently under way to assess microbiological efficiency and improve performance.