Appenzell Ausserrhoden drinking water meets PFAS safety limits

Authorities in Appenzell Ausserrhoden, Switzerland, have reported that public drinking water meets current and future legal limits for per- and polyfluorinated alkyl substances (PFAS). Following a comprehensive investigation by the Interkantonale Labor (IKL) in 2024 and 2025, water resources including spring and groundwater were tested to ensure compliance with the upcoming limit of 0.1 micrograms per liter.

While the distributed drinking water remains within safety standards, slightly elevated PFAS concentrations were detected in certain raw water sources in the Vorderland region. As a precaution, the affected water utilities have removed these specific sources from the drinking water network.

Technical challenges remain regarding the removal of ultra-short-chain PFAS, such as trifluoroacetic acid (TFA). Because these molecules are highly stable, water-soluble, and extremely small, conventional treatment methods like activated carbon filters often fail to capture them effectively.