The World Health Organization declared the occurrence of a human influenza pandemic due to the Influenza A (H1N1) 2009 virus on 11 June 2009. France had been preparing for this eventuality for several years, particularly through the French plan to prevent and control an influenza pandemic. At that time, the Agency was requested to assess the risks to workers, associated with the presence of the InfluenzaA (H1N1)2009 pandemic virus in wastewater.

Water is essential for the human body to function properly which is why so much importance is given to water supply and water quality. Surface waters and groundwater are the main sources used to provide tap water, or municipal water,  to the public. Tap water is treated to ensure compliance with about 60 microbiological, physico-chemical, radiological and organoleptic parameters described in European regulations which are transposed into national law. The extent of water treatment depends on the quality of the resource with the aim of eliminating pathogenic microorganisms such as bacteria, viruses, and parasites, chemical contaminants including for example pesticides and nitrates, and excess mineral salts like fluoride and sodium, among others.