<p>Chemicals used in agriculture and veterinary fields, as well as industrial waste and human activities, result in a decrease in water quality. Biological and chemical contaminants in drinking water pose serious health risks to humans. To ensure a safe and clean water supply, it is critical to employ detection methods that allow for rapid, sensitive, and on-site analysis. However, conventional chromatographic and mass spectrometric methods do not meet these requirements. In recent years, there has been a remarkable increase in the development of portable, cost-effective, sensitive, and specific techniques for detecting water contaminants. Biosensors are convenient tools that can be easily adapted to meet the needs of analysis. We aimed to emphasize the enhanced analytical performance of nanobiosensors constructed using different types of nanomaterials, such as gold nanoparticles, quantum dots, and magnetic nanoparticles, in water safety analysis, particularly for the detection of pathogenic bacteria, heavy metal ions, pesticides, and antibiotics. Furthermore, aptamer-conjugated nanoplatforms, which utilize aptamers instead of antibodies for the biological recognition of environmental pollutants, highlight the advantages of aptamers over antibodies in terms of cost, stability, specificity, and ease of conjugation with nanomaterials. This review highlights the importance of combining the unique physicochemical properties of nanoparticles with the high specificity and ease of modification of aptamers for rapid, sensitive, and on-site water safety monitoring. This integration enables biosensors to achieve lower detection limits, provide reliable measurements in complex environments, and be adapted to portable platforms.</p> Graphical abstract <p></p>