Version française Version française FRANCE : Quality of drinking water distributed by communal public services

The quality of tap water distributed to consumers depends on the quality of water in the river or groundwater bodies from which the water is taken and the treatments carried out subsequently.
Numerous controls are carried out throughout the drinking water production line: at the catchment point, at the water treatment plant, on the distribution networks, etc.
  • The resource: raw water
  • Tap water
  • Criteria and standards
 
© Ecology and sustainable development department
The resource: raw water
Water is very rarely drinkable in its natural state.
It may contain the following in varying proportions:
  • Dissolved materials from elements that water has flown through (magnesium, sodium, calcium, potassium, bicarbonates, sulphates, chlorides);
  • Suspended clay that may promote the development of bacteria that are always present in aquatic environments;
  • Organic materials resulting from the breakdown of animal and plant materials.
There may also be noxious elements from:
  • Discharges from treatment plants, factory waste, crop treatment products (fertiliser, pesticides, etc.);
  • Viral or bacterial pollution due to animal or human excrement evacuated through the soil or discharged into watercourses.
The raw water intended to supply drinking water distribution services is selected based on very specific physicochemical criteria. Certain bodies of water that do not fulfil these criteria may not be used for the production of drinking water. They must be protected against the various sources of pollution likely to render them unfit for human consumption.
 
 
 
 
 
Tap water: criteria and standards
In France, water intended for human consumption must fulfil numerous criteria:
  • Public health criteria: water without any health risk, even over the long term, based on the principle of precaution.
  • Comfort and pleasure criteria: water that is pleasant to drink, clear and balanced in mineral salts.
The criteria may be grouped together in 7 sets of parameters:
  • Organoleptic parameters - water colour, taste, odour and transparency - do not have any direct relation with health. Water may smell of chlorine and be perfectly drinkable;
  • Physicochemical characteristics acquired by water during its natural route;
  • Substances tolerated up to a certain threshold (fluoride, nitrate) or limited to an inconvenience for the user (iron);
  • Toxic substances for which tolerated levels are around one millionth per litre: lead, chromium, etc.
  • Microbiological parameters: pathogenic viruses and bacteria are excluded. As in any living environment, an inoffensive and limited bacterial life is allowed;
  • Pesticides and related products are limited to minute doses;
  • Softened water: authorised subject to a minimum level of calcium, magnesium, carbonate or bicarbonate.
© Ecology and sustainable development department
 
These highly stringent quality standards are based on medical work carried out by the World Health Organisation (WHO) with recommendations on the maximum acceptable doses to be respected, i.e. the quantity that individuals may absorb without any danger on a daily basis and throughout their lives. The maximum quantity contained in water is calculated on this basis, factoring in a large safety margin. If the standard is temporarily exceeded, this does not necessarily involve a risk for consumers.
 

Source : Ecology and sustainable development department

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