Drinking water distribution systems : assessing and reducing risks National Research Council (U.S.). Committee on Public Water Supply Distribution Systems: Assessing and Reducing Risks. & National Research Council (U.S.). Water Science and Technology Board.

The distribution system is a critical component of every drinking water utility. Its primary function is to provide the required water quantity and quality at a suitable pressure, and failure to do so is a serious system deficiency. Water quality may degrade during distribution because of the way water is treated or not treated before it is distributed, chemical and biological reactions that take place in the water during distribution, reactions between the water and distribution system materials, and contamination from external sources that occurs because of main breaks, leaks coupled with hydraulic transients, and improperly maintained storage facilities, among other things. Furthermore, special problems are posed by the utility's need to maintain suitable water quality at the consumers tap, and the quality changes that occur in consumers' plumbing, which is not owned or controlled by the utility. The primary driving force for managing and regulating distribution systems is protecting the health of the consumer, which becomes more difficult as our nation's distribution systems age and become more vulnerable to main breaks and leaks. Certainly, factors that cause water of poor aesthetic quality to be delivered to the tap, or that increase the cost of delivering water, are also important. Possibly because they are underground and out of sight, it is easy to delay investments in distribution systems when budgets are considered. Rather than wait for further deterioration, however, there is an urgent need for new science that will enable cost-effective treatment for distribution, and design, construction, and management of the distribution system for protection of public health and minimization of water quality degradation. This book focuses on public systems that serve at least 25 people much of the information is also applicable to private, individual systems. The book considers regulations and non-regulatory approaches to controlling quality; the health effects of distribution system contamination; physical, hydraulic, and water quality integrity; and premise plumbing issues. Important events that constitute health risks, such as cross connections and backflow, pressure transients, nitrification and microbial contamination associated permeation and leaching, repair and replacement of water mains. Corrosion control, and contamination in premise plumbing, was examined.

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