A cross-connection is an actual or potential connection between any part of a potable water system and any other environment that contains other substances that would allow such substances to enter the potable water system. Cross-connection control programs are intended to reduce the risk of contamination or pollution of the public water system. This fourth edition of AWWA Manual M14, Backflow Prevention and Cross-Connection Control, provides both technical and general guidance on the recommended procedures and practices for developing, operating, and maintaining a cross-connection control and backflow prevention program. This edition includes a new chapter on conducting a cross-connection control survey and expands the discussions on assessing the risks and preventing backflow. A greatly expanded appendix details how to test most backflow-prevention devices. Other issues covered include backflow prevention principles, assembly, application, installation, and maintenance; health and legal concerns; and detailed information on potential and real hazards. This manual is intended for use by all professionals charged with protecting the public water supply with proper backflow prevention and cross-connection control programs.