Legionella – Occurrence, incidence and diseases as well as technical influencing factors in buildings

Introduction

Legionella are bacteria that occur in natural and artificial water systems. They can pose a serious health risk in drinking water installations in buildings. In its legal framework, Switzerland distinguishes between drinking water as a foodstuff and shower water as an article of daily use. Drinking water is subject to foodstuffs legislation, while shower water is subject to the regulations for articles of daily use. This distinction determines the requirements for the monitoring and control of water installations, in particular for the prevention of legionella.

The Swiss Gas and Water Industry Association (SVGW) has created the W3/E4 guideline, a set of regulations that obliges operators of water supply systems to carry out self-monitoring. This is intended to ensure that the water quality in buildings meets the applicable hygiene requirements and that the risk of legionella proliferation is minimised as far as possible.