Since January 12, 2026, France has begun systematically testing tap water for twenty specific pollutants known as PFAS, which were not previously monitored on a regular basis. This change was mandated by a European Union directive adopted in December 2020, aimed at improving water quality monitoring. The directive was incorporated into French law through an ordinance in late 2022. As a result, some communities that were previously considered compliant with water quality standards now find themselves non-compliant. This is not because of new contamination, but because of the expanded testing framework. Before January 2026, only targeted inspections were conducted, without guaranteed coverage across the entire country. Now, PFAS are systematically tested at both the water source and at the consumer’s tap. The inclusion of PFAS in water quality control programs became mandatory in January 2026, but the French government decided to begin earlier, in 2025, to prepare for the new requirements. Local health authorities, known as ARS, were encouraged to integrate PFAS testing into their programs in advance. If a PFAS level is found to exceed the safety limit, local authorities can apply for a three-year temporary exemption, which can be renewed once, to implement solutions. During this time, water continues to be distributed but under increased monitoring until improvements are made. PFAS, or per- and polyfluoroalkyl substances, are known as “eternal pollutants” because they resist natural degradation. Their chemical structure, particularly the carbon-fluorine bond, makes them extremely stable and difficult to break down in the environment. This means they can persist in groundwater for decades and migrate through soil and water systems. PFAS are not inherently harmful unless they are measured, as they can only exceed regulatory limits once they are detected. These substances are found in a wide range of industrial and consumer products, including non-stick cookware, waterproof clothing, and fire-fighting foams. As a result, they often end up in the environment through industrial discharges or leaks. Removing PFAS from water is not possible using standard purification methods. Techniques like activated carbon filtration and reverse osmosis are effective but require specialized equipment, regular maintenance, and frequent replacement of filters. These measures come at a cost, which is passed on to residents through higher water bills. The number of monitored substances is expected to grow, as new PFAS compounds, such as trifluoroacetic acid (TFA), will soon be added to the regulatory list. While this expansion of monitoring reveals more about the extent of PFAS contamination, it also highlights the long-standing presence of these substances in the environment.