A project sponsored by American Water Works Association Research Foundation was undertaken to identify and develop Good Practices that can realistically be implemented by water utilities for preventing microbiological contamination associated with the installation, rehabilitation, and repair of water mains. This paper summarizes the most significant findings and recommendations of the project that include: sources of microbiological contamination; good practices for controlling microbiological contamination; benefits from and barriers to implementing good practices; and, recommendations for future directions. Includes 14 references.