Disinfecting Water Mains

This standard presents essential procedures for the disinfection of new and repaired potable water mains. Topics covered include forms of chlorine disinfection, a description of the disinfection procedure, preventive and corrective measures during construction, methods of chlorination, final flushing, bacteriological testing, redisinfection, final connections to existing mains, disinfection procedures when cutting into or repairing existing mains, and special procedures for caulked tapping sleeves. Appendixes cover chlorine residual testing, chlorine dosages, and disposal of heavily chlorinated water

According to the Centers for Disease Control and Prevention, 32 percent of waterborne disease outbreaks are caused by pathogen intrusion in the water distribution system. Incorporating disinfection practices for water mains and storage facilities can reduce the risk of microbial contamination. This handy guidebook provides all the correct field practices for preventing microbial contamination of the water flowing in water mains, storage tanks, and other distribution system components. NOTE TO WATER UTILITIES: To ensure that mains and storage facilities are properly disinfected prior to use, AWWA advises that water utilities should insist that their pipeline contractors have and use this book.

"The objective of this project was to identify and develop Good Practices that can realistically be implemented by water utilities for preventing microbiological contamination associated with the installation, rehabilitation, and repair of water mains." -- Executive summary.

Legionnaires' disease, a pneumonia caused by the Legionella bacterium, is the leading cause of reported waterborne disease outbreaks in the United States. Legionella occur naturally in water from many different environmental sources, but grow rapidly in the warm, stagnant conditions that can be found in engineered water systems such as cooling towers, building plumbing, and hot tubs. Humans are primarily exposed to Legionella through inhalation of contaminated aerosols into the respiratory system. Legionnaires' disease can be fatal, with between 3 and 33 percent of Legionella infections leading to death, and studies show the incidence of Legionnaires' disease in the United States increased five-fold from 2000 to 2017. Management of Legionella in Water Systems reviews the state of science on Legionella contamination of water systems, specifically the ecology and diagnosis. This report explores the process of transmission via water systems, quantification, prevention and control, and policy and training issues that affect the incidence of Legionnaires' disease. It also analyzes existing knowledge gaps and recommends research priorities moving forward.