Water Quality in Winterthur – Where Does the Drinking Water Come From?

The drinking water for Winterthur is sourced from the Töss groundwater stream (Linsental and Zell). Approximately 30 000 m³ – that is 30 million liters – are extracted daily. The quality is so high that no further treatment is required.

Water Supply

The Winterthur public utility supplies, in addition to the city itself, eleven surrounding municipalities. The water comes from nine groundwater catchments located in protected zones and is pumped into two reservoirs. Two-thirds of the water reaches households by natural gravity – entirely without pumps. The remaining third is lifted to higher reservoirs via twelve staged pumping stations.

Through the Kemptthal staged pumping station there is also a direct connection to the Zurich water supply, further enhancing supply security.

In addition, water is provided for 3 880 hydrants, firefighting reserves, and 130 public fountains.

Water Quality

Winterthur’s drinking water has a hardness of around 28 °fH (approximately 15.7 °dH). A conversion table can be found here. A detailed chemical-physical analysis is available here.

Water quality is continuously monitored by the public utility. However, their responsibility ends at the house connection – the owner is responsible for quality within the building.

Why Is a Drinking Water Test Useful?

Even though the public water supply meets the highest standards, contaminants can enter on the way to the tap – for example through old pipes, fixtures, or stagnant water. These can release heavy metals, bacteria, or other residues into the water.

A professional laboratory analysis provides certainty and protects especially vulnerable people such as infants or pregnant women.

• Stadtwerke Winterthur
• Swiss Association for Gas and Water (SVGW)
• Ordinance on Drinking Water (PDF)