La pollution de l’eau douce

Commissariat général au développement durableJan 28, 2026

La pollution de l’eau douce, en surface (lacs, rivières, etc.) ou souterraine (nappes phréatiques-, est un problème majeur, car elle touche les écosystèmes, l’eau potable et donc notre santé. Les activités humaines dégradent les ressources d’eau en produisant des polluants difficiles à éliminer et qui s’accumulent dans la nature. Explications et état des lieux de la situation en France.

Freshwater pollution, whether on the surface (lakes, rivers, etc.) or underground (groundwater), is a major problem because it affects ecosystems, drinking water, and therefore our health. Human activities degrade water resources by producing pollutants that are difficult to eliminate and accumulate in nature. Explanation and overview of the situation in France.

5 chapters

What is the link between water pollution and health?
Water pollution sources
• In France, chemical pollution is one of the main causes of degradation in surface waters and groundwater. It originates from human activities: • intensive agriculture: nitrates, phosphates, pesticides, etc. • industry: heavy metals, polluting gases, hot water that alters ecosystems, etc. • domestic uses: household products, DIY products, hygiene and cosmetic items, etc. • land or maritime transport: hydrocarbons, metals, etc. • Treatment plants eliminate much of this pollution, but not completely. Some pollutants, particularly micropollutants, end up in aquatic environments and drinking water.
Health impacts of water pollution
Water pollution can cause illness. Some have infectious origins (gastroenteritis, viral hepatitis, legionellosis), while others are linked to chemical pollution. Their nature and severity depend on the type of pollutant, dose, and exposure duration. Water pollution is a major public health issue.
Water pollution: monitoring and trends
Monitoring
• Approximately 11,600 lakes, rivers, coastal waters, and 690 groundwater bodies are regularly monitored, producing over 21 million analyses per year, three-quarters of which target pesticides. • Water supply distribution networks underwent more than 18 million analyses in 2022.
Trends
• According to the latest Environmental Report (2024), the overall situation tends to improve: • 43.6% of French surface water bodies show good or very good ecological status in 2022 (versus 41.4% in 2010) • 67.9% of surface and groundwater bodies have good chemical status in 2022 (versus 51.2% and 58.9% respectively in 2010) • However, the report highlights some concerns: • water quality regarding nitrates is not improving, despite recent drops in nitrogen use (nitrate is one form of nitrogen). Concentrations remain stable in aquifers and rivers. Northern France is more affected than the south. • pesticides are present in most aquifers and rivers, including substances banned long ago. In 2022, France remains Europe's leading user of plant protection products (pesticides used specifically on vegetation). • pollution is a major cause of drinking water intake closures, often linked to nitrates and pesticides. • €16.2 billion was spent in 2022 to combat water pollution. Financial resources deployed increased an average of 1.3% annually over the past five years.
Pollutants in aquatic environments
Pesticides
Pesticides are chemical substances primarily intended to improve crop yields by controlling weeds and insects harmful to their growth. These active substances are highly diverse and may have other uses. Pesticides and their residues contaminate surface waters and groundwater aquifers.
Nitrates
Nitrates are a form of nitrogen that plays a very important role in crop growth. When used in excess, they leach through soils or reach rivers they contaminate. The presence of nitrates destroys the environments where they accumulate and has negative effects on animals and humans.
Micropollutants
• Micropollutants are small substances resulting from the degradation of larger materials produced by human activities. Present in water, air, and soils, they include microplastics, PFAS, and pharmaceutical residues. Even at low doses, their mixture can have severe effects on ecosystems and health. Over 100,000 molecules are already recorded in Europe. • Micropollutants: invisible water pollution • Micropollutants from agriculture, industry, transport, construction, and our domestic habits are released into aquatic environments at very low concentrations. They have harmful effects on biodiversity, our water resources, and our health. We can take action at our level and in our daily lives to prevent these unwanted and invisible pollutants from contaminating our environment.
Medications
Medication residues, poorly eliminated by treatment plants, contaminate rivers and groundwater, with biological effects even at very low doses. These substances can alter reproduction and behavior of species. Their presence also promotes antibiotic resistance, a global public health challenge.
Protecting aquatic environments
Overseas Water Plan
In overseas departments and regions, more than half the population lacks connection to treatment plants. Public sanitation services struggle to keep pace with demographic growth and ensure proper maintenance. Since 2016, the Water Plan has helped communities improve the situation through financing, expertise, and improvement contracts.
Implemented actions
To address environmental and health problems caused by water pollution, rules and actions are being implemented at national and international levels. Below is a selection of sites and pages dedicated to various initiatives.
French strategies and action plans
Contributions from the Water Assemblies Provisions of the Ecophyto2+ plan The micropollutants plan 2016-2021
International commitments
The convention for the protection of the marine environment of the Northeast Atlantic (OSPAR) Main texts on water The water framework directive (WFD)
Public resources
Metropolitan basins
• Water management in metropolitan France is organized around 7 hydrographic basins. There are 6 water agencies that collect data on the physical, chemical, and biological quality of aquatic environments. This data is made available to the public. • Adour-Garonne • Artois-Picardie • Loire-Bretagne • Rhin-Meuse • Rhône-Méditerranée et Corse • Seine-Normandie
Overseas basins
• Overseas, there are 5 basins and 5 water offices: • Guadeloupe • Guyane • Martinique • La Réunion • Mayotte

Further reading

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