Water Supply and Sanitation (WSS) in the European Union (EU) is the responsibility of each member state, but in the 21st century union-wide policies have come into effect. Water resources are limited and supply and sanitation systems are under pressure from urbanisation and climate change. The water policy of the EU is primarily codified in three directives:
EU member states have enacted national legislation in accordance with these directives. The institutional organisation of public water supply and sanitation does not fall under the purview of the EU, but remains a prerogative of each member state.
The Council Directive on Urban Waste Water Treatment concerns the collection, treatment and discharge of urban waste water and the treatment and discharge of waste water from certain industrial sectors. Its aim is to protect the environment from any adverse effects due to discharge of such waters.
According to the directive's timetable:
However, in the case of Spain changes were made at the time of transposing the Directive. In Article 2 of the Directive, a collecting system means "a system of conduits which collects and conducts urban waste water" and therefore all sewers and drains, both public and private were included. However, in the Spanish transposition (Real Decreto-Ley 11/1995 of 28 December 1995), the definition of a collecting system was changed to mean “all systems of conduits which collect and conduct urban waste water, from the municipal sewer and drainage networks and go to the treatment plants.” The added words mean that when the Spanish definition is applied to Article 3 of the Directive the municipal sewer and drainage networks are excluded. If the municipal network did not exist, as in the case of many urbanisations (housing estates) developed in the 1960s and 1970s and within agglomerations of over 2000 p.e. no collecting system needed to be provided at all, under the Real Decreto-Ley 11/1995. Obviously if waste water is not collected it cannot be treated, therefore the changed definition also affected Article 4 of the Directive. Even so, Spain had to and still has to comply fully with the Directive. On 5 March 2009, the Catalan Autonomous Government finally approved a law (La Llei de la millora d’urbanizacions) to deal with deficits of infrastructures, such as sewers in urbanisations in Catalonia, 18 years after the Directive was approved by the European Parliament.
The directive also allows the establishment of less sensitive coastal areas, for which primary treatment would be sufficient, if it can be shown that there is no adverse impact on the environment (Art. 6).