After revelations that its mineral water had been filtered, Henniez can no longer use the activated-carbon filters that once removed traces of pesticides. The Swiss bottler, owned by Nestlé Waters, must now stop using part of the water from some springs and instead adjust the blend of remaining sources so that the final product complies with legal limits. The information comes from documents obtained by RTS after two years of transparency requests.
In January 2024 it emerged that Henniez had filtered its so-called natural mineral water with activated carbon. Under Swiss law, mineral water must be naturally pure to carry that label. More problematic still, the filtration—used to remove pesticide residues—had been carried out without informing the public or regulators. Henniez was subsequently required to dismantle the filtration system.
Some water sources discarded
A report by the Vaud cantonal chemist from March 2023 shows that, after filtration stopped, certain sources must not be used. In practice, this means that water from some springs contains such high levels of pesticide residues—notably chlorothalonil—that it cannot always be used.
Nestlé Waters confirms that some water is not bottled, though it describes the process differently. Water that is not used simply continues its natural course through soil, groundwater and rivers, the company told a consumer programme on RTS.
Blending the remaining sources
Since filtration ended, Henniez has sought to reduce—rather than eliminate—pesticide residues. It does so by adjusting the mix of water drawn from different springs so that the final blend remains within legal limits.
Documents show that blending sources with different contamination levels was part of the company’s plan to continue production after removing the filters. In a presentation from November 2021 to Vaud authorities and the federal food-safety office, Nestlé Waters proposed managing the mix of sources to stay below legal thresholds, while acknowledging the reputational risks if contamination became public.
The company says blending sources is not new and had been done previously for other operational reasons.
A filtration system used for years
The documents also reveal the timeline of the filtration system: activated-carbon filters were installed in 2008, discovered by authorities in 2020 and dismantled in 2022. For roughly 14 years, water that had been filtered—like tap water—was sold as natural mineral water, a product that commands a higher price.
Despite the controversy, the company maintains that the water posed no health risk and that its mineral water has always been safe to drink.
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