M63, Aquifer Storage and Recovery provides a general understanding of the principles of aquifer storage and recovery (ASR). The manual discusses the concept, regulations as they are applied nationally and by state, basic design and development criteria, and presents results of an inventory of ASR well sites nationally. Both successful projects and ones that faced challenges are profiled. M63 provides management, operations, and engineering staff with an understanding of ASR to help them make decisions on investigations and installations when problems or the need to expand supplies arise, as well as enough background to improve response to problems and challenges. Chapters include: Groundwater Recharge and Storage Programs Regulatory Requirements Summary of ASR Programs in the United States Challenges for ASR Programs in the United States Planning and Construction of ASR Systems Operation and Performance Monitoring of ASR Wells Example ASR Programs in US ASR Versus Other Groundwater Recharge and Storage Programs"