Bathing water quality
The assessment of bathing waters is made on the basis of hygienic quality using E.coli and intestinal enterococci. They provide indications on the effectiveness of water protection measures and in particular the extent to which waste water treatment plants are fulfilling their function. Good hygienic quality of bathing water is essential to ensure that the population can bathe in rivers and lakes without any risk to health.
- Bathing water quality (open data)
Thanks to various preventive measures and major efforts in waste water treatment over the last few decades, the bathing water quality of Swiss rivers and lakes is very good today: It is possible to bathe in lakes and rivers in Switzerland almost everywhere without any health risks.
Only after heavy rainfall or during flooding is it advisable not to bathe in rivers: bacteria adhere to suspended particles and these may be ingested by bathers if they swallow the water. In the case of rivers and streams which act as receiving water courses for waste water treatment plants, increased volumes of waste water may be introduced as a result of storm overflows and can adversely affect hygienic conditions.
In the case of bathing water of limited quality, in accordance with the Waters Protection Ordinance, the authorities must take measures such as better water protection, upgrading of wastewater treatment plants or closing direct discharges, or explicitly advising against bathing. It can therefore be assumed that there will be a positive development in the quality of bathing water in the future.
Compared with other European countries, the quality of Swiss bathing water is very good: As is the case in only a few other countries, even major rivers and lakes in Switzerland are inviting bathing waters with outstanding quality.
Assessment of bathing water quality is carried out on the basis of cantonal water monitoring data relating to the hygienic parameters E. coli and intestinal enterococci (faecal bacteria). The EEA classification system applies to the quality assessment according to the EU Bathing Water Directive of 2006 (see table 3, section 7 of the Recommendation for the Assessment of Bathing Waters).The EEA classification can only be calculated on the basis of a series of measurements of at least four bathing seasons, with four samples per season.