Commission Delegated Decision (EU) 2024/1441 establishing a methodology for the measurement of microplastics in water intended for human consumption of 11 March 2024 supplementing Directive (EU) 2020/2184 on the quality of water intended for human consumption was published in the Official Journal of the European Union on 21 May 2024.
For example, methods for sampling and analysis are given in the appendix, which are intended to improve the comparability of the results.
You can find the delegated decision here:
https://eur-lex.europa.eu/legal-content/DE/TXT/?uri=OJ:L_202401441