Water scarcity is no longer limited to historically dry regions of Southern Europe. In recent months, large parts of the continent have come under increasing pressure from prolonged dry weather, including Hungary. According to the European Drought Observatory, drought conditions remained critical and further intensified across parts of Central and Western Europe in July 2026, with alert conditions affecting areas from France and southern Germany to Hungary and Romania.
Climate change is already having visible impacts across the continent. In Germany, low water levels in major rivers are affecting shipping and industries, while England's 2025 drought led to water restrictions affecting millions of people and historically low reservoir levels. Hungary is facing similar challenges: according to the National Directorate General for Water Management, the country has accumulated a precipitation deficit of 462 mm over the past five years, while groundwater levels across the Great Hungarian Plain have fallen by 1-2 metres below the 30-year average.
Against this backdrop, cities, municipalities and infrastructure operators face an increasingly urgent question: How can reliable water sources be secured in the face of longer drought periods, rising temperatures and growing demand?
For Dr. Stephan Wasielewski, Head of Water Infrastructure at Drees & Sommer and an environmental engineer with more than a decade of experience in research and practice, the challenge is clear:
“Increasingly, water is available in the wrong place at the wrong time. Long dry periods are followed by intense rainfall that soils and drainage systems can barely absorb. Managing these extremes is becoming one of the key infrastructure challenges of our time.”
According to Drees & Sommer, the focus should now be on recirculating water for longer, reducing losses and making better use of existing resources.
1. Keep rainwater where it falls
In many cities, rainwater is still discharged as quickly as possible. As drought periods become more frequent, this approach is increasingly problematic. Infiltration areas, green roofs, retention systems and cisterns help retain water locally and replenish groundwater reserves.
A practical example comes from Berlin, where Drees & Sommer supported the district of Lichtenberg in identifying schools that can be disconnected from the sewer network. On around 135,000 square metres of sealed surfaces, equivalent to more than 19 football fields, green and infiltration areas as well as swales and infiltration systems are being developed to keep rainwater where it falls and reduce runoff into the sewer network.
2. Reduce water losses in infrastructure networks
Water scarcity is not only caused by drought. Aging infrastructure can result in substantial losses of valuable drinking water.
Digital leak detection, continuous monitoring and the modernization of existing networks can significantly reduce losses and improve resource efficiency. Innovative technologies, including AI-based forecasting tools, are already helping utilities detect potential pipe failures before major leaks occur.
3. Reuse water whenever possible
Not every application requires drinking-water quality. Rainwater, greywater and process water can often be reused for irrigation, technical systems or industrial applications.
“We need to move beyond the linear model of extraction, consumption and disposal. Future-proof regions will be those that keep water in circulation and use it multiple times. This will also play an increasingly important role in industrial decision-making,” says Wasielewski.
For the Alzchem Group in southern Germany, Drees & Sommer is assessing how process water from the company's central wastewater treatment plant can be treated and reused multiple times within operations, helping to reduce overall freshwater consumption.
4. Improve transparency in water management
As water becomes scarcer, competition between municipalities, industries, agriculture and energy providers increases. Digital tools can help decision-makers understand how much water is available, who is using it and where shortages may arise.
Ireland, for example, maintains a national Water Abstraction Register to improve transparency around water use and licensing.
5. Increase green infrastructure in cities
Sealed surfaces such as asphalt and concrete prevent water from infiltrating into the ground. Green spaces, trees and climate-adapted landscaping help retain water, improve local microclimates and reduce urban heat.
One example is the Telegrafenberg campus in Potsdam, near Berlin. In 2025, Drees & Sommer developed a landscape concept for the 27-hectare site on behalf of the GFZ Helmholtz Centre for Geosciences. The need for action is significant: around 78% of the trees on the campus have already been affected by heat and drought. The concept includes climate-adapted planting that requires considerably less water than parts of the existing tree stock, some of which is more than 100 years old, helping to stabilize the site's water balance in the long term.
Households can contribute, but infrastructure is key
Households can contribute through measures such as rain barrels, cisterns and water-saving fixtures. However, the greatest impact will come from investments in infrastructure, stormwater management and water reuse systems.
“What matters now is how quickly cities and municipalities prepare for changing climate conditions and increasing pressure on water resources,” says Wasielewski.