Full Description

This study investigated 16 repair sites of drinkingwater mains to monitor the effect of main repairs onwater quality. Samples were collected from the distributionsystem and from the soil and groundwater surroundingthe mains. Changes in water quality outsidethe isolated repair area were also monitored.A total of 424 water samples collected from consumers'homes and flushed hydrants were assayed fortotal coliforms, Escherichia coli, and aerobicendospores. Total coliforms were detected in 4.0% ofthese samples and E. coli in only a single sample.Almost all of the positive samples (16 of 17) were collectedduring the flushing step of the repair process.Water quality changes, including losses of chlorineresiduals and peaks in turbidity, were also observedoutside the repair area.Repairs of water mains are routinely conductedby water utilities, and, moreover, the frequency ofrepairs in some systems can be quite high becauseof the system's age and resulting deterioration.Water utilities should have measures in place toensure that their operational practices are adequatefor public health protection as well as for regulatorycompliance. Includes 36 references, tables, figures.

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Edition: Vol. 100 - No. 7 Published: 07/01/2008 Number of Pages: 15 File Size: 1 file , 730 KB