Distribution Water Quality Issues Related to New Development or Low Usage

One cause of distribution system water quality problems is from low usage due to new developments or reduced demand. Low usage causes increased water age throughout the system which can lead to a number of water quality problems, including decreased disinfectant residual, sedimentation, increased temperatures, and taste, odor, and color problems. To address these issues and maintain compliance with regulatory standards, utilities have implemented design/construction and O&M based best management practices (BMPs) with varying success.


The objectives of this project were to (1) identify water quality changes that occur in the distribution system as a result of low or diminished use areas, in particular, areas of new development with low initial customer usage and established areas undergoing diminished use; and (2) recommend best management practices (BMPs) on minimizing water quality problems in such areas. Utilities must provide potable water to small and large users, new and old developments, and central and remote customers while accounting for changing demographics and demand patterns. In order to maintain adequate water quality and satisfy all of these needs, water utility operators must have the ability to choose sound design and O&M-based BMPs, and defend their decisions.



The development of the DST software in this research project allows utility operators to do this by providing a method to compare the costs and benefits of various BMPs and thus make better decisions. The companion CD-ROM contains a decision support tool for selecting the most appropriate BMP for reducing water quality problems due to low usage.