Commission decides to refer Ireland to the Court of Justice of the European Union for failing to comply with EU rules for treating urban waste water

Today, the European Commission decided to refer Ireland back to the Court of Justice of the European Union with a request to impose financial sanctions for failing to comply with the judgment in case C-427/17, Commission v. Ireland  of 28 March 2019. In this judgment, Ireland was found to have breached the requirements of the Urban Waste Water Treatment Directive (Council Directive 91/271/EEC) in 28 agglomerations. Untreated urban waste water can put human health at risk and pollute lakes, rivers, soil and coastal and groundwater.  

The Directive protects both water quality and human health by requiring that Member States collect and treat their urban waste water before it is discharged into the environment. Under the Directive, Member States must have collecting systems for agglomerations with a population of 2 000 and more. Moreover, Member States must apply secondary treatment to urban waste water before discharge, and, in large agglomerations (population of 10 000 and more) which discharges in a zone sensitive to eutrophication, a more stringent treatment is required (removal of nitrates or phosphorus, which act as fertilisers). 

Since the judgment in case C-427/17, Ireland has made progress in resolving issues of compliance in 20 of the agglomerations covered by the judgment. However, eight agglomerations remain in breach. In six agglomerations Ireland has failed to ensure that overflows from urban waste water collecting systems are sufficiently controlled and appropriately treated. In two further agglomerations, Ireland has failed to ensure that the urban waste water that enters the collecting systems are subject, before discharge, to secondary treatment or an equivalent treatment. Furthermore, in one agglomeration, the urban waste water is discharged to a sensitive area without being subject to a more stringent treatment.  

The Commission sent Ireland a letter of formal notice under Article 260(2) TFEU on 14 November 2024. The Commission considers that efforts by the Irish authorities have, to date, been insufficient to comply with the first judgment and is therefore referring Ireland to the Court of Justice of the European Union for a second time, with a request to impose financial sanctions. 

Background 

Under the Urban Waste Water Treatment Directive, Member States must have collecting systems in place for all agglomerations with at least 2 000 inhabitants. Where the establishment of a collecting system is not justified, notably because it would entail excessive cost, individual or other appropriate systems can be used instead, provided they achieve the same level of environmental protection. Member States must also secure that discharges from urban wastewater treatment plants serving agglomerations with at least 2 000 inhabitants comply at least the secondary treatment level (which involves treating organic matter in urban wastewater) before being released in the environment. If an agglomeration discharges its waste water into a sensitive area, then it must ensure that they are subject to a treatment that is stricter than the secondary one.  

More Information 

EU infringement procedure 

Infringement decisions database and infringements map and graphs  

December 2025 infringements package

Infringement procedure Ireland (INFR(2013)2056)