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WATERBORNE OUTBREAKS CAUSED BY DISTRIBUTION SYSTEM DEFICIENCIES IN THE UNITED STATES
Citation:
Craun, G. F. AND R L. Calderon. WATERBORNE OUTBREAKS CAUSED BY DISTRIBUTION SYSTEM DEFICIENCIES IN THE UNITED STATES. AMERICAN WATER WORKS ASSOCIATION, RESEARCH AND TECHNOLOGY. AWWA Research Foundation, Denver, CO, 93(9):64-78, (2001).
Description:
Distribution system contamination has caused a significant number of waterborne outbreaks in the United States. The number of illnesses in a distribution-system outbreak can be quite large, and illness can be severe resulting in hospitalization and sometimes death. During the 113 distribution-associated outbreaks reported since 1971, 498 persons were hospitalized, and nine deaths occurred. Other unrecognized outbreaks likely occurred. Since 1995, distribution system deficiencies have caused 45% of all outbreaks reported in community systems, whereas, the inadequate treatment of ground and surface water has caused 20% and 15% of the outbreaks, respectively. Chemical and microbial contamination from cross-connections and backsiphonage caused most of the distribution-associated outbreaks. More attention should be placed on preventing contamination of the distribution system to further reduce the risk of waterborne outbreaks. Important activities include maintaining adequate water pressures throughout the system, identifying and replacing older, leaking water mains, maintaining a chlorine residual and monitoring the residual in the system, adopting cross-connection control programs, routinely inspecting storage facilities, adequately disinfecting after system repairs, and increasing corrosion control efforts.