Tierfed groundwater pumping station: No PFOA in the groundwater

27.10.2026 – In May 2026, an official sampling exercise took place at the Tierfed groundwater pumping station operated by Kraftwerke Linth-Limmern AG (KLL). This revealed a PFOA level that exceeded the maximum limit set out in the Drinking Water Ordinance. An in-depth investigation into the causes has now revealed that the groundwater from the Tierfed pumping station is of impeccable quality. The elevated PFOA level recorded in May 2026 was confined to the sampling valve at the pumping station.

In brief:

• The cause of the elevated PFOA level was investigated in depth. No elevated PFOA levels were found in the drinking water from the Tierfed groundwater pumping station. 

• The investigations identified the sampling valve at the pumping station as the source of the elevated PFOA level.  

• The sampling valve was replaced and the drinking water supply from the Tierfed groundwater pumping station resumed.

   

Due to the elevated PFOA level, the relevant authorities decided on 22 June 2026 to take the pumping station out of service immediately. KLL AG 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 was thus maintained. Those affected by the measure were 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.

In-depth analyses of the groundwater from the Tierfed pumping station have shown that the groundwater does not contain elevated levels of PFOA. The quality of the drinking water for consumers and the drinking water for livestock has been and remains impeccable at all times. However, an elevated PFOA level was detected in the sampling valve of the groundwater pumping station. This fitting is used to take drinking water samples and does not come into contact with the drinking water supplied to consumers. The sampling valve has since been replaced, tested and found to be in perfect condition. The drinking water supply from the pumping station was resumed following official approval.

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. Common sources of PFOA include sewage sludge applied in the past, fire-fighting water or 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.