Geneva’s water quality

Top quality through intensive monitoring

Geneva's water is soft and very clean. Water in most sectors has a hardness of 13.5°fH, and nitrate levels under 3 mg/l. Sector Arve has slightly higher nitrate levels (5.1 mg/L), but still very comfortably below the legal upper limit of 40 mg/L. It is also harder at 20°fH. (which is still moderately soft water).

The limits for soft water are at around 15°fH. These units define the amount of dissolved minerals in the water, especially the ions of magnesium and calcium. Those can form substances that do not readily dissolve (known as lime scale).
To ensure this high quality and subsequent popularity of its drinking water, SIG (Service Industriels de Genève) takes up to 6000 samples and 90000 analyses are made annually. Samples are taken mostly at treatment plants, but also in other parts of the system such as reservoirs or public fountains.