Drinking water

A well-functioning infrastructure is needed to ensure that consumers are supplied with sufficient amounts of good quality drinking water at all times, even in situations of severe shortage . This system is regulated by the Ordinance of 19 August 2020 on Guaranteeing Supplies of Drinking Water in Situations of Severe Shortage (DWSO).

The dry summers of 2003, 2015, 2018 and 2022 made it clear that a functioning drinking water supply cannot be taken for granted, even in Switzerland, with its many lakes and rivers. Furthermore, the many different ways in which water is used can cause problems; for example, the demands on water for agricultural use and domestic consumption conflict with the requirements of water protection and with water suppliers.

The aim of the DWSO is to ensure that the population can be supplied with sufficient drinking water even in the event of a severe shortage. The cantons, in conjunction with their communes and local water companies, ensure that the regions are supplied from a number of different water supply points or that they are networked. This means that, in the event of drought or damaged supply infrastructure, water can be drawn from various points so that sufficient water is available for use.

The DWSO states that, in situations of severe shortage, each member of the population must receive at least four litres of drinking water per day from the fourth day onwards. Local authority crisis organisations are responsible for this emergency supply until the mains water supply returns to normal operation. All members of the population must have enough water in store to cover their needs for the first three days (including drinking water).

Water suppliers must protect their systems against external influences such as sabotage. In order to guarantee the supply of water, they must have two sources from which water is drawn. They must also check drinking water quality more frequently during a shortage.