Tierfed groundwater pumping station disconnected due to elevated PFOA levels

03.07.2026 - During an official sampling exercise at the Tierfed groundwater pumping station operated by Kraftwerke Linth-Limmern AG, a PFOA level was detected that exceeds the maximum limit set out in the Drinking Water Ordinance. The Tierfed groundwater pumping station was immediately shut down following an official order. The drinking water supply for consumers remains guaranteed. The most recent sample, taken in February 2026, met the requirements for drinking water quality.

In brief:

• As part of routine sampling carried out by the Office for Food Safety and Animal Health of the cantons of Graubünden and Glarus, an elevated PFOA level was detected at the Tierfed groundwater pumping station operated by Kraftwerke Linth-Limmern AG (KLL).
• The affected customers have been switched to the Linthal drinking water supply (municipality of Glarus South); the drinking water supply remains guaranteed.
• The cause of the elevated PFOA level is currently being investigated. PFOA (perfluorooctanoic acid) belongs to the group of substances known as per- and polyfluoroalkyl substances (PFAS).

On 22 June 2026, the relevant authorities decided to take the pumping station out of service immediately. KLL implemented this on the very same day and switched the water supply to the Linthal drinking water supply (municipality of Glarus South). The drinking water supply for the population remains guaranteed. Those affected by this measure are KLL’s direct customers as well as the affected customers in the Wald supply zone of the Linthal municipal drinking water supply (municipality of Glarus South). They were informed by KLL about the switch in the drinking water supply.

The measured PFOA level (1.3 µg/l) exceeded the maximum limit specified in the Drinking Water Ordinance (0.5 µg/l) by 0.8 µg/l. However, in the most recent sample taken in February 2026, the PFOA level was below the specified maximum limit and the drinking water was of impeccable quality. Over the past few weeks, the municipality of Glarus South has tested the drinking water from its water supply for PFAS. The samples taken met the requirements for drinking water quality.

In consultation with the relevant cantonal authorities, a plan is currently being drawn up to investigate the cause of the detected exceedance of the maximum limit. At the same time, a monitoring programme for PFAS is being established at the Tierfed groundwater pumping station. Consumers will be informed of the results of the investigations and the next steps as soon as further findings are available.

Kraftwerke Linth-Limmern AG is a joint venture between Axpo and the Canton of Glarus. Axpo holds 85 per cent of the shares, whilst the Canton of Glarus holds 15 per cent.

Note for editorial teams

• PFOA and PFAS: PFOA (perfluorooctanoic acid) belongs to the group of per- and polyfluoroalkyl substances (abbreviated to PFAS). These substances are highly persistent in the environment and can accumulate over long periods of time. Common sources of PFOA include sewage sludge applied in the past, fire-fighting water and industrial emissions. A single detection of elevated levels does not automatically indicate an immediate health risk, but does require further investigation into how the PFOA entered the environment.