This book 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 activites; 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, sports centers, commercial buildings and transport terminals.This publication is one of a series of supporting documents that provide guidance on implementing the World Health Organization's "Guidelines for Drinking-water Quality." It is intended to support the improvement of water safety within buildings.The target audience for this book 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. This book is intended to be a useful resource for the development of training and information material.