RIWA-Rijn’s new Annual Report 2025 provides an up-to-date picture of the quality of the Rhine as a source of drinking water. The report looks not only at what is measured in the river, but above all at what is needed to prevent pollution at source.
In 2025, the ERM target values used by RIWA-Rijn to assess water quality were thoroughly revised. For more than 1,500 substances and several groups of substances, the concentrations considered compatible with a well-protected drinking water source were reassessed. Based on these updated target values, 86 measured parameters exceeded the desired level at least once in 2025. The purification task also shows that the level of treatment required for drinking water production is still not decreasing structurally.
The report also addresses both emerging and existing risks to the Rhine’s water quality. Developments involving lithium extraction, processing and recycling remain a concern, while monitoring data in 2025 also revealed a notable peak in PFBS discharges in the Leverkusen area. These examples highlight the importance of continuous monitoring, transparency on emissions and a permitting system that keeps pace with new knowledge.
The Annual Report also shows how new analytical techniques can help identify risks at an earlier stage, and how cooperation beyond the water sector can contribute to cleaner water. One example is the CLEAR-water project, which examines how the use of gadolinium-based contrast agents in MRI scans can be reduced.
The central message therefore remains unchanged: what does not enter the Rhine does not have to be removed later. Protecting the Rhine as a source of drinking water requires continuous monitoring, sound permitting and cooperation across the entire river basin.
Note: an English version of the 2025 Annual Report will be published in October.