Persistent Pockets of Low Chlorine Residual in New York City's Drinking Water Distribution System: A Case Study

Abstract

Key TakeawaysPockets of low chlorine residual have been found in New York City's water distribution system, with fluctuating water demand resulting from the seasonal operation of local institutions.Variations of the chlorine residual profiles in one such pocket were found through both field and laboratory investigations.Once the cast‐iron pipe was replaced with ductile‐iron pipe in the study area, an acceptable chlorine residual was usually maintained; when low chlorine residuals were observed, low‐velocity flushing remediated the situation.