How Switzerland manages water resources with neighbouring countries

A German-flagged cargo ship on the Rhine in Basel in June 2025. Keystone / Georgios Kefalas

Switzerland holds 6% of Europe’s water reserves. Who decides how to use the rivers and lakes that cross national borders? Professor Christian Bréthaut explains the agreements, priorities and conflicts - and the unresolved case of Lake Maggiore.

Water management has once again become an urgent issue amid the ongoing drought conditions in Europe. Last week, Swiss Environment Minister Albert Rösti announced a review of the national water strategy. This is an issue that concerns not only the Swiss federal government, but also its relations with its neighbours.

Switzerland is known as Europe’s “water tower”. But this hides a complex reality: managing this resource means constantly negotiating with neighbouring states. Every river flowing from the Alps and every shared lake is a potential source of conflict or cooperation.

Christian Bréthaut, an expert in water governance at the University of Geneva, explained to Swiss public broadcaster RSI how these mechanisms actually work – and why climate change means tensions are likely to increase.

Switzerland holds 6% of Europe’s water

Switzerland covers only a small fraction of Europe’s territory, yet it holds around 6% of the continent’s freshwater reserves. Its glaciers, lakes and rivers are a remarkable natural asset, but one that extends far beyond its borders. The Ticino flows into Italy’s Po River, the Rhine winds its way towards Germany and the Netherlands, and the Rhône crosses France before reaching the Mediterranean Sea.

This geographical position makes Switzerland a key player in water diplomacy. But it also involves huge responsibilities: every decision taken in Bern can have consequences hundreds of kilometres away.

Who makes the decisions in the event of a drought?

The most difficult question arises when water is in short supply, as it has been this year. Who has priority? Households needing water for domestic use? Farmers who need to irrigate their crops? Hydroelectric power stations or factories that use water to cool their machinery?

“Priorities are set according to the most critical safety needs,” Bréthaut told RSI. “The supply of drinking water is the cornerstone. Water is a fundamental human right; we mustn’t forget that. Then there are food security and energy security.”

The problem is that there is currently a lack of precise data on actual consumption for different uses. “It is essential to gain a better understanding of this consumption in order to be able to work out how and when to set priorities,” the expert warns.

Agreements that work: the Rhine, the Rhône and Lake Constance

Not all of Switzerland’s cross-border waters are managed in the same way. Some arrangements work very well, while others remain sources of conflict.

In the north and west, the situation is under control. “The Rhine, the Danube and Lake Constance are very well-regulated cases; I would say they are exemplary in terms of cross-border water resource management,” explains the professor, who is also co-director of the UNESCO Chair in Hydropolitics. “There are operational committees and clearly defined responsibilities among the stakeholders for managing crises.”

Switzerland has also made decisive progress with France following years of negotiations. In 2025, two historic agreements were signed: one for Lake Geneva and the other for the Rhône.External link The negotiations began in 2011, when France was facing a severe drought.

“These agreements help to pre-empt potential tensions which, with climate change, are becoming more acute,” he told RSI. “They establish forums for discussion not only regarding the current situation but also for crisis situations. Agreements already exist for most European rivers; the Rhône has long been an exception.”

The unresolved case: Lake Maggiore

South of the Alps, however, the situation is more complicated. Lake Maggiore remains an unresolved issue between canton Ticino and Italy. Italy wants to raise the lake’s water level to ensure water supplies for agriculture in the Po Valley. But canton Ticino fears flooding in the Locarno area. This year, Piedmont asked the Ticino authorities to increase the flow of water into Lake Maggiore,External link which has been at very low levels for some time, but the cantonal government refusedExternal link, as there is already too little water to meet the canton’s own needs.

According to Bréthaut, Swiss federalism is a strength, but it has its limits. “Our federalism and the principle of subsidiarity mean that the cantons are on the front line when it comes to managing this sort of crisis. They are the ones who know the challenges and the mechanisms of good neighbourly relations better than anyone else.”

However, he emphasises that when local tensions become diplomatic issues, Bern must step in. “These issues quickly reach the highest levels of politics. The Swiss federal government must commit to supporting the cantonal authorities in their discussions with neighbouring states.”

Political action

The management of Lake Maggiore is not currently governed by an international treaty on an equal footing, unlike Lake Lugano, which is governed by a 1955 convention, or Lake Geneva, where the agreement between Switzerland and France includes specific quantitative provisions.

To fill this legal vacuum, Ticino parliamentarian Bruno Storni has tabled a motion in Bern backed by 28 co-signatories. The text formally calls on the Federal Council to initiate bilateral negotiations with Italy to reach a fair and sustainable international convention.

Bern’s position, as expressed by Environment Minister Albert Rösti, is cautious but firmExternal link: “A decision on the future definitive regulation would require an agreement between Switzerland and Italy. However, the Federal Council would not conclude such an agreement against the will of canton Ticino.”

The Federal Office for the Environment is currently monitoring the situation to ensure that the trial phase agreed for this year, does not exceed safety limits for Swiss territory.

Is a supranational body needed?

Faced with increasingly frequent crises, some people have called for the creation of an international body to manage water from the top down. Bréthaut is sceptical. “The challenges associated with drought are highly context-specific. I doubt that the international level is the most appropriate for setting priorities and making decisions.”

It is better to focus on flexible bilateral agreements, the expert argues. “At the international level, we have numerous frameworks that enable us to define fundamental principles: international law conventions or the UN Sustainable Development Goals. These commitments should enable us to anticipate crises or manage them when they occur.”

The problem is that international law is being eroded. Increasingly, there are situations where negotiations no longer work or where states withdraw from signed agreements. This is why the Swiss federal government – through the Geneva Water HubExternal link and the Blue Peace programmeExternal link – continues to promote water as an instrument of peace.

“Switzerland is a recognised player in this field. I hope it will continue to make a long-term commitment to cooperation in the water sector, and not just in disaster response,” says Bréthaut.

The future: more tensions, even in Switzerland

Rösti’s recent announcementExternal link that he intends to review the national water strategy confirms that the issue has become a priority. “I am very curious to see how the government intends to structure this new approach to water management at national level,” says the Geneva-based professor. “Regional and inter-cantonal tensions will intensify. The government’s role in managing these conflicts will become increasingly important.”

Switzerland, Europe’s ‘water tower’, will have to learn to manage a resource that is no longer as abundant as it once was. And it will have to do so by negotiating on several fronts: with the cantons and neighbouring countries, while taking into account that the climate is changing – and, consequently, so are the rules of the game.

Translated from Italian, sub-edited by Alexandra Andrist/sb