From sewers to swimming sites: how Europe’s cities reclaim their rivers

Europe’s cities are opening their rivers back to swimmers. From Paris to Berlin, officials are racing to clean up centuries-old waterways, betting that a swimmable river is now essential urban infrastructure, not a luxury, as heatwaves intensify and summers get harder to survive.

When Paris opened the Seine to public swimming last year, it wasn’t just a headline-grabbing stunt tied to the Olympics. It was the visible tip of a larger shift across Europe: cities are starting to see their rivers and canals not as engineering problems hidden behind concrete embankments, but as public spaces worth restoring, protecting and living alongside.

“European cities definitely are increasingly investing in the rivers and also the canals that are connecting the rivers, because they can provide multiple benefits at once,” says Vassileios Latinos, head of resilience and climate adaptation at ICLEI Europe, a network of local and regional governments working on sustainability. From Paris to Copenhagen to Berlin, he says, cities are rediscovering their waterways as tools for climate resilience, public health and everyday urban life, often all at once.

The numbers back up the shift

The optimism isn’t just anecdotal. According to Trine Christiansen, head of the freshwater and environment group at the European Environment Agency, the continent’s bathing waters are generally in good shape. In the EEA’s most recent assessment, 85 percent of Europe’s bathing sites were rated excellent, and 96 percent met at least minimum quality standards.

These figures have steadily improved since the EU’s Bathing Water Directive was revised. The share of poor-quality sites fell from 2.4 percent to 1.5 percent, while excellent-rated sites climbed to nearly 85 percent.

Still, gaps remain, particularly for cities pushing to make urban rivers swimmable, rather than just the coastlines and lakes the directive was originally built around. France, the Netherlands and Estonia currently have some of the highest shares of poor-quality bathing waters in the EU, often linked to inland rivers rather than the sea.

Why are cities doing this now

For Latinos, the motivation goes well beyond nostalgia for a swimmable river. It’s a response to a warming climate. “Having clean and integrated waterways and rivers within the city can be a powerful tool for helping cities to cope with more frequent and intense heat waves,” he says, pointing to the extreme heat that hit Europe just weeks before our conversation.

Rivers, canals and the green space around them “can create natural cooling, they can reduce the urban heat island effect… and provide accessible places where people can find relief during extreme temperatures.”

He describes watching Paris’s riverside promenades, deliberately redesigned as pedestrian-friendly public space, become “basically packed” during the recent heatwave. In his city, Berlin, the local government is “revitalising the waterways through green corridors and public access projects,” often working with NGOs and citizen groups pushing to reconnect residents with the water.

The appeal, Latinos argues, is that river restoration delivers several benefits from a single investment: flood risk management, biodiversity gains, cooler streets, attractive public space and a boost for local economies all bundled into one project. It’s also, he suggests, a statement of intent. “It’s also like a way to show that the city basically cares about the urban environment.”

The hard part: cleaning the water

None of this works without first tackling water quality, and that’s where the real complexity lies. Eline Boelee, an expert in water and health at the Dutch research institute Deltares, points to the continent’s ageing infrastructure as a core problem.

Many European cities still rely on combined sewer systems that carry both rainwater and sewage. “The systems are built for an average, and when heavy rainfall comes, the capacity is sometimes surpassed and that water is flushed into surface water,” she explains. This poses risks including pathogens, antimicrobial-resistant bacteria and increasingly chemical pollutants like PFAS.

Latinos frames the fix in structural terms. Making a river swimmable, he says, requires reducing pollution at its source, upgrading wastewater and stormwater systems, restoring the natural ecosystem and critically building a proper monitoring system so cities and citizens know when water is genuinely safe.

Coordination is the real bottleneck

If there’s a single obstacle cities keep running into, it isn’t the science but people and money. “It’s not that when someone makes a decision, this can be done within months,” Latinos says. Rivers cross multiple jurisdictions and involve utilities, businesses and local communities whose interests don’t always align, especially when restoration work means closing riverside businesses for months. “There is a need for coordinated action and strong leadership from the beginning,” he says, along with technical expertise and, just as important, patched-together funding from diverse sources.