Extreme weather events, including floods and droughts, are increasing in frequency and intensity. They affect the operation of water-supply, drainage and sewerage infrastructure, and the functioning of wastewater treatment plants, thereby affecting the protection of public health. Parties to the Protocol on Water and Health reviewed experience and good practice in Europe through a broad consultative process, to devise the present guidance. This publication describes how adaptation policies should consider the new risks from extreme weather events, how vulnerabilities can be identified and which management procedures can be applied to ensure sustained protection of health. It takes an integrated environment-and-health approach and addresses cross-cutting issues, such as the role of the health and environment sectors in extreme weather, the need for policy dialogue and multisectoral partnership to assess and control risks, and the challenges of different settings (such as urban and rural, small and centralized large-scale supplies). The publication is aimed at a broad audience, including policy-makers; environment, health and water-resources professionals; and water service managers.