Executive summary -- 1. Background and introduction -- 2. Literature review -- 3. Materials and methods -- 4. Changes in disinfection by-products and water quality in full-scale distribution systems -- 5. Guidelines to select distribution system sampling locations for disinfection by-product monitoring -- 6. Summary, conclusions, and recommendations -- Appendix A. Microbial degradation of HAAs and other DBPs -- Appendix B. Batch incubation in bottles -- Appendix C. Correlations between DBP concentrations, water age, and water quality parameters -- Appendix D. Effects of pipe material, pipe diameter, booster chlorination station, and storage reservoirs -- Appendix E. Inter-laboratory comparison experiments -- References -- Abbreviations.