Swimming areas with poor water quality doubled
This year, 280 swimming locations received at least one warning, almost twice as many as the 142 in the same period last year.
Published on August 13, 2025
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Warning for swimmers: the number of locations with unsafe swimming water has doubled. This year, 280 locations received at least one safety warning, compared to 142 last year. This is according to an analysis by press agency ANP of data from Zwemwater.nl. Blue-green algae and bacteria are making swimming risky in more and more places. Despite these challenges, people can still cool off safely at almost 800 other locations during the hot summer days.
Risks mapped
The doubling of the number of swimming locations with a safety warning is a significant increase. Of the Dutch swimming waters, 17% are facing health risks, an increase from 10% at the end of June. This means that of all potential swimming locations, a significant proportion are currently considered unsafe. The data comes from Zwemwater.nl, a website that provides up-to-date information on water quality in the Netherlands. This increase in risky locations emphasizes the importance of continuous monitoring and timely warnings. The Zwemwater.nl website is an initiative to inform swimmers so that they can make an informed decision before entering the water. The type of risk varies from blue-green algae to excessive concentrations of bacteria.
Causes of the deterioration in water quality
The current warm temperatures are contributing to the deterioration in water quality. High temperatures promote the growth of blue-green algae, a bacterium that can produce toxic substances. These substances can cause skin irritation, stomach problems, and in some cases even neurological problems. In addition, the warm conditions can increase the concentration of certain bacteria, which also poses a risk to public health. The combination of these factors means that water quality requires extra attention during the summer months. Local authorities and water managers must remain alert and take measures to minimize the risks. These measures include putting up warning signs and carrying out additional checks.
The impact on the construction sector
Water quality problems not only affect recreation but also the construction sector. The construction sector has been concerned for some time about the poor water quality in ditches and rivers, as this can delay housing construction. Pollution from PFAS, microplastics, and fertilizers is a major problem that has a negative impact on the granting of building permits. Last year, Bouwend Nederland, Aedes, and NEPROM emphasized that construction projects could come to a standstill if water quality does not improve. The current doubling of the number of swimming locations with poor water quality underscores the urgency of this problem. It is essential that innovative solutions are found to improve water quality and minimize the negative impact on the construction sector.
Innovative solutions and collaboration
Despite the challenges, various innovative solutions are being developed to improve water quality. Researchers at Wetsus have developed a method to remove and neutralize PFAS from water. In addition, innovative techniques such as 3D phased array weather radar and hybrid AI models can contribute to better water management and climate adaptation.
The PHARA project is developing a 3D phased array weather radar to better predict extreme weather conditions, and hybrid AI models can help manage groundwater resources and predict pollution. Cooperation between different sectors is crucial to tackle the water quality crisis. Construction companies, nature organizations, water companies, and the government must work together to achieve stable groundwater levels and better water purification.
Measures and prevention
In addition to technological innovations, there are also measures that citizens can take themselves to protect water quality. It is important not to leave litter in nature and not to discharge harmful substances into the sewer system. Reducing the use of pesticides in the garden can also contribute to better water quality. Governments can enforce stricter rules regarding the emission of harmful substances by businesses and agriculture. In addition, it is important to invest in green infrastructure, such as green roofs and permeable paving, to improve rainwater drainage and reduce the load on the sewer system. Climate-adaptive construction and the use of green infrastructure are crucial for a sustainable future.
The role of the government
The government plays a crucial role in ensuring water quality. It is the government's responsibility to establish and enforce laws and regulations that protect water quality. In addition, the government must invest in research and innovation to develop new technologies that can improve water quality. It is also important that the government works together with other parties, such as water companies, nature organizations, and the construction sector, to achieve an integrated approach to water quality issues.
