While combating waterborne diseases remains a major challenge in developing countries, tap water in France, as in other developed countries, undergoes quality control to ensure it meets food safety standards. Some small rural water systems, particularly those in mountainous areas, exhibit microbial contamination—often linked to the presence of animals in the watershed—which is much more common than in the water systems of large cities.

Restrictive recommendations apply to certain vulnerable populations. Individuals with severe immunodeficiency, such as those living with HIV, are advised not to drink tap water to avoid any risk of infection. Water with a nitrate content exceeding 50 mg/L is not recommended for infants and pregnant women.

Infectious Diseases

Water contamination by microorganisms can lead to:

• Acute gastroenteritis, which, when of bacterial origin, can lead to complications such as dyspepsia (chronic abdominal pain due to loss of elasticity in the intestinal wall) or serious complications such as reactive arthritis, Guillain-Barré syndrome, and hemolytic uremic syndrome.

• Viral hepatitis A or E.

• Stomach ulcers or cancers associated with Helicobacter pylori.

• Legionellosis, especially in immunocompromised individuals, etc.

Diseases linked to chemical pollution

Diseases linked to chemical pollution depend on numerous factors such as:

• the type of pollutant,

• the exposure dose,

• the duration of exposure.

France benefits from regular monitoring of drinking water quality, and the management of toxic risks is contingent upon compliance with quality limits for toxic compounds. However, meeting potability limits for certain pollutants, such as arsenic—which require costly treatment—is sometimes difficult for small municipalities to achieve within the timeframes mandated by regulations.

The French Agency for Food, Environmental and Occupational Health & Safety (ANSES) is responsible for assessing the health risks associated with exceedances of quality limits and reference values for water intended for human consumption for each of the parameters listed in the Public Health Code.

Health issues linked to chemical water pollution may include:

• occasional cases of poisoning, most often linked to a deterioration in water quality inside buildings (release of lead or copper),

• but above all cancers resulting from chronic exposure (over 10 years and up to 40 years). These diseases account for most of the health conditions associated with chemical pollutants in drinking water observed today. Various cancer sites have been linked to arsenic in drinking water (skin, bladder, kidney, and lung cancers) and to chlorination byproducts (bladder and colorectal cancers). The difficulty in reconstructing past exposures and accounting for the many other risk factors (tobacco, diet, etc.) for these types of cancers often explains the discrepancies observed in epidemiological studies.

More recently, the adverse effects of certain water pollutants on reproduction and fetal development have been suggested, though no conclusive evidence has been provided to support the existence of a risk. For example, the numerous epidemiological studies on chlorination byproducts have not, to date, identified a link between these compounds and effects on reproduction and development.

The risk associated with the presence of drug residues in natural waters, through the consumption of tap water produced from these natural waters, remains hypothetical. This hypothesis is based more on the large number of molecules involved than on the concentrations reached by a given molecule in tap water. Regardless of the molecule in question, the dose absorbed through water consumption over a lifetime remains below a daily therapeutic dose. Currently, no epidemiological data indicate any effect on human health.

This table was compiled by Santé publique France based on international literature and its own research.