This publication, Guidelines for Climate Proofing Investment in the Water Sector: Water Supply and Sanitation, presents a step-by-step methodological approach to assist project teams in managing climate change risk in the context of water supply and sanitation investment projects. The provision of water supply and sanitation services is particularly vulnerable to projected changes in climate conditions (temperature and precipitation among others), in the frequency and intensity of extreme weather events, as well as and in the projected rise in sea-level and the intensification of storm surges. The process of climate proofing investment projects aims both at assessing the climate risk to a project’s future costs and benefits, and undertaking a technical and economic analysis of options to alleviate or mitigate those risks.