The proper treatment of used water is a key responsibility of cities, and the enforcement may be with local authorities. Member States shall ensure that all agglomerations with a population equivalent (p.e.) of between 2 000 and 15 000, and more than 15 000 are provided with collecting systems for urban wastewater (Art. 3). Where the establishment of a collecting system is not justified, either because it would produce no environmental benefit or because it would involve excessive cost, individual systems or other appropriate systems which achieve the same level of environmental protection shall be used. It is mandatory that urban wastewater entering collecting systems shall before discharge be subject to secondary treatment or an equivalent treatment (Art. 4). For sensitive areas (as defined following the criteria in Annex II), the urban wastewater entering collecting systems shall before discharge be subject to even more stringent treatment than that described in Art. 4 for all discharges from agglomerations of more than 10 000 p.e. (Art. 5). Discharges to freshwater and estuaries from agglomerations of less than 2 000 p.e. and discharges to coastal waters from agglomerations of less than 10 000 p.e. are subject to appropriate treatment before discharge happens (Art. 7). Monitoring activities to verify the compliance with the requirements must be in place and performed by competent authorities and appropriate bodies (Art. 15).

Since its adoption the quality of European rivers, lakes and seas has greatly improved. However, a number of important aspects are not addressed by the Directive, such as pollution remains (including pollution from smaller cities outside the scope of the Directive and pollution caused by storm water overflows) and micropollutants such as residues from pharmaceuticals and cosmetics. Therefore, the Directive is currently under review.

On 25 October 2022, the European Commission published the proposal for the new Urban Wastewater Treatment Directive (UWWTD). The Commission has proposed to expand the scope of the Directive to include smaller towns (from 1 000 p.e.) to collect and treat water. The Commission also proposed to set up local integrated urban wastewater management plans to prevent sewer overflows (these plans can include more green areas to retain and infiltrate rainwater, which also have many benefits for the urban environment like preventing heat islands), as well as requirements for large and selected wastewater treatment plants to remove micropollutants and nutrients. Finally, the Commission proposes that the wastewater energy sector should be energy neutral by 2040 by increasing the production of e.g. biogas from sludge.

More details about the proposal for a new Urban Wastewater Treatment Directive can be found here: https://ec.europa.eu/commission/presscorner/detail/en/QANDA_22_6281

The 2019 evaluation of the Directive found that it is overall very effective when fully implemented. The reduction of organic matter and other pollution in treated wastewater has improved water quality throughout the EU. The evaluation found that implementing the Directive has been expensive, but the benefits clearly outweigh the costs. The Staff Working Document on the Evaluation of the Urban Wastewater Treatment Directive summarises the results of the evaluation including a summary of implementation of the UWWTD and status of compliance per Member State: https://ec.europa.eu/environment/water/water-urbanwaste/pdf/UWWTD%20Evaluation%20SWD%20448-701%20web.pdf

• Date of document: 21/05/1991
• Date of effect: 29/05/1991; Entry into force Date notif.
• Date of notification: 29/05/1991
• Date of transposition: 30/06/1993; At the latest See Art 19
• Date of end of validity: No end date