One of twelve water treatment technology units, this student manual on distribution systems provides instructional materials for six competencies. (The twelve units are designed for a continuing education training course for public water supply operators.) The competencies focus on the following areas: types of pipe for distribution systems, types of valves in water systems, meter types, disinfecting lines and storage tanks, clear well storage and elevated storage, and storage tank parts. For each competency, student objectives, resources (information sheets and appendix materials), learning activities, and evaluation activities are provided. The appendices contain information sheets on materials and meters, valves, valve maintenance, disinfecting mains and storage tanks, and recoating storage tanks. Generally, an evaluation form with answer key is provided for each competency. (JH)