This problem is somehow circumvented, since most existing water-supply systems have difficulties in meeting these standards, and the new ongoing constructions mentioned in previous sections are in line with currently less stringent international accepted standards (e.g. WHO or EU). It also identifies a list of 341 chemical substances for which sanitary maximum allowable concentrations are established, including ammonia, fluorine, sulphates, (heavy) metals and organic micropollutants. In accordance with the 2000 Law on Water Supply and Wastewater, drinking water sources should be protected through pollution prevention measures in order to meet the requirements of sanitary and environmental legislation.