One of twelve water treatment technology units, this student manual on cross connections provides instructional materials for two competencies. (The twelve units are designed for a continuing education training course for public water supply operators.) The competencies focus on cross connections terminology and control devices. For each competency, student objectives, resources (information sheets, references to manuals, and appendix materials), learning activities, and evaluation activities are provided. The appendices contain information sheets on cross connections, public health significance of cross connections, cross connections and backflow prevention regulations, and required backflow prevention devices. Evaluation forms with answer keys are provided for each competency. (JH)