Drought and pollution put Swiss drinking water under pressure

Around 400 water specialists are gathering in Zurich as Switzerland confronts mounting pressure on the resource that flows from almost every household tap. The first EurEau Water Summit in Switzerland brings together representatives from drinking water, wastewater and water protection organisations from Switzerland and abroad. Its main event is scheduled for Wednesday.

The meeting comes as climate change alters water availability and raises the frequency of dry periods. Chemical contaminants are also appearing in groundwater at concentrations that place greater demands on local supplies. At the same time, public authorities and utilities face rising expectations for water quality and the cost of maintaining infrastructure.

The Swiss Association for Water, Gas and Heat and the Swiss Association of Wastewater and Water Protection Experts say these issues require cooperation across borders and sectors. Water does not follow administrative boundaries, and pollution entering a catchment area can affect communities far from its original source.

Switzerland has substantial water resources, but availability varies by season and location. Smaller catchment areas can face shortages during prolonged dry periods, even when national supplies appear adequate. That regional exposure gives the discussions in Zurich immediate practical importance.

Around 80% of Switzerland's drinking water comes from groundwater, according to the conference material. That dependence makes the protection of aquifers a frontline task for municipalities, farmers, industry and environmental authorities.

Around 60% of drinking water can currently be supplied without treatment or after simple treatment. The arrangement keeps energy use and operating costs relatively low, but it relies on preventing pollutants from reaching underground reserves. Once chemical contaminants enter groundwater, removing them can require extensive manpower, energy and finance. In some cases, treatment may not be possible at all.

The risks include trace substances and other chemical pollutants that are increasingly complicating the work of local water suppliers. Higher quality expectations add another layer of pressure. Utilities must monitor supplies closely and invest in treatment systems when prevention fails.

The emphasis from the water sector is therefore shifting toward source protection. Safeguarding recharge zones, managing land use around wells and limiting pollution at its origin can protect supplies more efficiently than relying solely on expensive treatment plants. For Swiss communities, the condition of the ground beneath farms, forests and settlements is directly linked to the reliability of the tap above it.

Sponge landscapes are being presented as one way to make Switzerland more resilient to both drought and heavy rainfall. The approach aims to retain rain in soils, wetlands, moors, forests, rivers and wider catchment areas rather than allowing it to run off quickly.

Better retention can help reduce drought stress and support groundwater recharge. It can also moderate peak flows, limit erosion and create or restore habitats. The same landscape measures may benefit agricultural crops, forest health, soil fertility, biodiversity and recreation.

This matters because water shortages can develop locally even in a country with sufficient water overall. Longer dry periods place particular strain on smaller catchments, where communities have fewer alternatives if wells or streams weaken. Rain that remains in the landscape can provide a buffer during dry spells and reduce the speed and force of runoff during intense storms.

The proposal does not replace drinking water infrastructure or pollution controls. It complements them by treating the landscape as part of the water system. Planning decisions about wetlands, forests, farmland and development therefore affect both ecological resilience and the future cost of supplying safe water.

EurEau links 38 national organisations across 33 countries, reflecting the cross-border nature of the problems facing water providers. The Zurich summit gives Swiss utilities and authorities a forum to compare responses to drought, pollution, quality standards and infrastructure costs.

The financial challenge is substantial even when a supply remains technically secure. Removing chemical contaminants can demand new treatment equipment, more energy, additional staff and long-term monitoring. Upgrading pipes, wastewater plants and protection systems also requires reliable financing from public authorities and consumers.

Climate change complicates investment decisions. Utilities must prepare for longer dry periods while also managing sudden rainfall and pollution events. Measures that protect catchments can reduce future treatment costs, but they often require coordination among municipalities, farmers, landowners and environmental agencies.

For Switzerland, the debate reaches beyond the water sector. Groundwater protection affects spatial planning, agriculture, energy use and biodiversity policy. The decisions taken in the coming years will shape how much of the country's drinking water can continue to receive no treatment or only simple treatment. The summit places those choices within a wider European discussion, while the implementation will remain largely local and regional.