Because of the Bureau of Reclamation (Reclamation) and industry concerns, Reclamation has undertaken a 2-year collaborative study with the AWWA Research Foundation to address problems associated with prestressed concrete pipe. Since protecting the investment is a top priority, efforts are initially and primarily being directed towards identifying diagnostic techniques which reliably assess the condition of pipe inservice as well as exploring ways to economically repair or rehabilitate distressed pipe with minimal service disruption. Assumptions used in current design methodologies as well as the effectiveness of the engineering provisions which better protect the pipe from potentially destructive environments are also being analyzed. This paper addresses one critical phase of the overall program, the repair and rehabilitation phase, and one topic from the phase, namely the research, development, implementation, and monitoring of the new and unique repairs that were performed on the Central Arizona Project siphons. Although these repairs were performed on large diameter pipe, they would be applicable to small sizes as well.