Cross-connection control is one of the most important barriers in the multiple-barrier approach drinking water suppliers use to protect public health. Contamination of a drinking water distribution system through a cross-connection often results in immediate adverse health effects - illness or even death. This Manual provides a total cross-connection control program for your water system. The manual explains how cross-connections and backflow can occur and tells you how to choose, install, and maintain backflow prevention devices. You ll learn the water purveyor 's legal responsibilities, as well as the customer 's responsibilities in backflow prevention. The manual covers risk assessment, types of programs to consider, and program administration. Until the cross connection control program is fully developed, the water purveyor is at maximum risk of potential liability.