The region of Eastern Switzerland but also the cantons of Zurich, Zug and Aargau remain the worst affected by the drought. In many eastern regions it has not rained for weeks. 

The lack of rainfall and precipitation has severely diminished groundwater levels, say the relevant authorities. According to the Federal Office for the Environment, natural aquifers and groundwater supplies have been steadily decreasing over the last three months  – with dry earth reaching up to one metre into the ground.

While drinking water levels are still not threatened, the dry season is having an impact on rivers and lakes. Fish are dying as water levels shrink and water temperatures rise, according to Sonia Seneviratne, a scientist with Zurich's ETH, who was talking to Swiss broadcaster SRF.

Fish in the Thun river have had to be relocated to the southern stretch of the watercourse due to low water levels. Such measures have become a common precaution in recent summers, Dominik Bonderer, head of communications at the Office for Waste, Water, Energy and Air in the canton of Zurich, told SRF.

The dry summer has also seen wildfire warnings raised. The fire department were deployed to extinguish 20 alone in the last week, reports SRF. Three cantons – Valais, Ticino and Graubunden – have introduced a ban on lighting any kind of outdoor fires.

“The danger of forest fires is marked as high,” states a warning from Switzerland's Federal Office for the Environment. 

Meanwhile, areas in the canton of Thurgau have placed a ban on farmers pumping water, as has the canton of Aargau. Lake Constance and the Rhine are excluded from the ban. 

Thunderstorms and heavy rainfall are forecast in parts of western Switzerland this weekend, although such downpours are not expected to make much of a difference to groundwater levels.

Last month “was the driest June for over 100 years,” writes the Federal Office for Meteorology and Climatology in its monthly report. “Despite persistent thunderstorms in the first half of the month, precipitation in some regions remained well below average.” 

With little relief to the drought in sight, further bans on extracting water are expected to come into place in the coming days, with citizens cautioned to reduce water usage in many areas. 

There is no suggestion however that drinking water levels could be affected. 

READ MORE: Summer in April: parts of Switzerland see record temperatures