Nationally, water utilities suffer some 250,000 to 300,000 main breaks yearly that cause total losses of about $3 billion per year. To mitigate these losses, utilities require effective strategies to assess condition, compute risk, and implement pipe renewal projects. Planning for mitigation requires valid estimates of the probability of failure, and providing these estimates has been the goal of a series of research projects, including this one. The project team attempted to develop and test main break models. Efforts included data collection, data cleaning and quality control, verification, and application to utility case studies. The work clarified that the link between main break models and risk factors is in the predictor variables that show risk of breaks. The project was able to model some types of breaks in single utilities with a fair degree of confidence, but many questions remained about usefulness of results within the utilities. The project also produced guidance for quality assurance of main break data.