The objective of the Directive is to protect the environment from the adverse effects of urban waste water discharges. For this purpose, it concerns the collection, treatment and discharge of urban waste water and the treatment and discharge of waste water from certain industrial sectors. The areas into which urban waste water entering collecting systems shall be discharged are divided into: (a) sensitive areas; and (b) less sensitive areas. According to the criteria given in Annex II, the former include: (a) natural freshwater lakes, other freshwater bodies, estuaries and coastal waters which are found to be eutrophic or which in the near future may become eutrophic if protective action is not taken; (b) surface freshwater intended for the abstraction of drinking water; (c) areas where further treatment than that prescribed in this Directive is necessary to fulfil Council Directives. As far as the latter is concerned the following elements shall be taken into consideration when identifying less sensitive areas: open bays, estuaries and other coastal waters with a good water exchange and not subject to eutrophication or oxygen depletion or which are considered unlikely to become eutrophic or to develop oxygen depletion due to the discharge of urban waste water. Annex I concerns the requirements for urban waste water. In particular, it regards collecting systems, the discharge from urban waste water treatment plants to receiving waters, industrial waste water, reference methods for monitoring and evaluation of results. Further provisions concern the reuse of treated waste water whenever appropriate.
Council Directive 91/271/EEC concerning urban waste water treatment.