AWWA JAW54682

Distribution system contamination has resulted in a significant number of waterborne disease outbreaks in the United States. A review of the 113 distribution-associated outbreaks reported over the past 30 years finds 498 hospitalizations and nine deaths. Since 1996, distribution system deficiencies have caused 45% of all outbreaks reported in community water systems. Most distribution-associated outbreaks were attributable to chemical and microbial contamination from cross-connections and backsiphonage. Preventing contamination of the distribution system is key to reducing the risk of waterborne disease outbreaks. Important preventive steps include maintaining adequate water pressure throughout the system; identifying and replacing older, leaking water mains; maintaining a chlorine residual and routinely monitoring the residual; adopting cross-connection control programs; inspecting storage facilities on a routine basis; adequately disinfecting after system repairs; and increasing corrosion control efforts. An aging water system infrastructure renders the United States even more vulnerable to the risk of waterborne disease outbreaks. More regulations may be required to prevent these outbreaks unless water suppliers take action to reduce distribution system contamination and sufficient funds are allocated for system maintenance, repair, and replacement. Includes 22 references, tables.