Water quality Confederation instructs cantons to implement drinking water remediation

SDA

29.1.2025 - 11:01

According to the report, around a tenth of the population consumed drinking water that exceeded the maximum level for chlorothalonil between 2019 and 2021. (symbolic image)
According to the report, around a tenth of the population consumed drinking water that exceeded the maximum level for chlorothalonil between 2019 and 2021. (symbolic image)
Keystone

The federal government has instructed the cantons to closely monitor the implementation of drinking water remediation. Most water suppliers have already initiated appropriate remediation measures to reduce the active ingredient of the plant protection product chlorothalonil.

Keystone-SDA

Plant protection products containing the active ingredient chlorothalonil have been used in Switzerland since the 1970s, as the Federal Food Safety and Veterinary Office (FSVO) revealed in a report to Parliament on Wednesday. Due to health concerns, the federal government banned the plant protection products on January 1, 2020. However, degradation products of chlorothalonil can still be found in groundwater and drinking water.

Drinking water remediation measures include mixing with uncontaminated water, temporarily closing contaminated wells or purchasing water from neighboring water supplies. Technical treatment plants should only be installed if the measures that can be implemented quickly are not possible or have already been exhausted. The treatment of contaminated water should not be a permanent solution. The focus should be on precautionary water protection so that harmful substances do not reach the groundwater in the first place.

According to the FSVO, the estimated investment costs for the treatment of drinking water would be between CHF 54 million and CHF 818 million, depending on the variant. The total annual costs would amount to between CHF 13 million and CHF 74 million.

According to estimates in the report, an average of one tenth of the population consumed drinking water that exceeded the maximum level for chlorothalonil between 2019 and 2021. The proportion of the population affected by contaminated drinking water will decrease significantly over the next 5 to 15 years due to the natural decline in concentrations in groundwater.