Extensive experience shows that poor design and management of water systems in buildings can cause outbreaks of disease. The types of building, water uses, disease outcomes and individuals affected are diverse. The health risks are preventable and can be readily controlled. However, evidence from outbreak detection suggests that the overall trend is increasing. With increasing global urbanization, the overall exposure of the human population to poorly designed or managed water systems in buildings is increasing rapidly. Consequently, the risk of disease outbreaks is also increasing. Actions to reduce the risk of disease should be considered a public health priority. This document provides guidance for managing water supplies in buildings where people may drink water; use water for food preparation; wash, shower, swim or use water for other recreational activities; or be exposed to aerosols produced by water-using devices, such as cooling towers. These uses occur in a variety of buildings, such as hospitals, schools, child and aged care, medical and dental facilities, hotels, apartment blocks, sport centres, commercial buildings and transport terminals. The target audience for this document includes the full range of "actors" who influence the overall safe management of building water supplies. In particular, it is directed at those who design, construct, manage, operate, maintain and regulate building water systems.