This document was developed by the U.S. Environmental Protection Agency, Indoor Environments Division. It provides practical guidance on how to control moisture in buildings.1 It is not a textbook, code or standard. Chapter 1 focuses on principles of moisture control: how water moves into and within a building and why the movement of water should be controlled or managed. Chapters 2, 3 and 4 provide profession-specific guidance for the design, construction and maintenance phases of a building’s life. To illustrate how core concepts and principles relate to each stage of a building’s life, each guidance chapter contains hyperlinks to relevant principles described in Chapter 1 and other related material throughout the text. Each guidance chapter also includes methods for verifying the appropriate implementation of the moisture control recommendations and a reference section that identifies additional related resources for readers interested in more detailed information.