The revised Urban Waste Water Treatment Directive (Directive (EU) 2024/3019) becomes applicable from 1 August 2027 for the provisions explicitly flagged for deferred application — Articles 12 and 13 and Annexes II and IV. source 14
At legislation level, it is recorded as in force and with a general date of application of 1 August 2027. legislation record
If you tell me which obligation you’re tracking (e.g., energy neutrality, quaternary treatment/micropollutants, monitoring/reporting), I can point you to the exact article and the relevant phased deadlines for different plant sizes.