In February 2004, after numerous studies and deliberation, the we implemented chloramination in our distribution system. The driver for changing the distribution system disinfectant from chlorine to chloramine was to comply with Federal and State water quality regulations. The primary objective was to reduce the formation of trihalomethanes (THMs), haloacetic acids (HAAs), and regulated chemical by-products of disinfection that may cause adverse health effects. Chloramine is very effective at limiting the formation of these by-products. In addition, due to the large size of our water system, maintaining a small concentration of disinfectant throughout the pipe network and storage system is necessary to preserve water quality. Chloramine, since it is less reactive than chlorine, is ideal for meeting this secondary objective.
After the implementation of chloramination, the predicted improvements were realized (e.g., concentrations of THMs decreased by 50 percent) and extensive water quality monitoring was conducted as well as monitoring customer responses. Overall the results were positive. Some individuals, however, did express concerns about the amount of information available about health issues associated with chloramine, the decision to convert the system to chloramine and alleged effects such as skin rashes and digestive disturbances. Since these concerns were expressed, we have met with and listened to concerned individuals, consulted with the medical community, held public meetings, reviewed the literature, conducted tests, engaged water professionals, surveyed other utilities, compiled analyses and posted information to the web-site. As a product of this effort, listed below are responses to frequently asked questions about chloramine and their researched responses. These responses are scientific in nature and are tailored to an informed audience while still providing general information for the average concerned citizen.
Questions and Answers Regarding Chloramine
A number of questions have been posed to us and the California Department of Health Services in regard to the conversion from chlorine to chloramine for distribution system disinfection as listed below by topic area. Click on the attachment below to view the following topics:
The following staff from the City and County of San Francisco was involved in the development and review:
Andrzej Wilczak, SFPUC, Water Quality Division
June Weintraub, San Francisco Department of Public Health
Manouchehr Boozarpour, SFPUC, Water Quality Division
Andrew DeGraca, SFPUC, Water Quality Division
In the course of developing these responses, the we consulted with a number of health and water quality professionals to obtain feedback, review and comments to improve and ensure maximum accuracy. A debt of gratitude is owed to:
Erica Brown, Association of Metropolitan Water Agencies
Gary Burlingame, Philadelphia Water Department
Phillippe Daniel, CDM
Jeffrey Griffiths, Tufts University
Darren Lyttle, United States Environmental Protection Agency
Catherine Ma, California Department of Health Services
Christine Owen, Tampa Bay Water
Chris Rayburn, American Water Works Association Research Foundation
Michael Schock, United States Environmental Protection Agency
Richard Valentine, University of Iowa
Brian Zamora, Environmental Health, San Mateo County
Review by the above individuals in no way constitutes endorsement, nor reflects official positions of their respective organizations. The SFPUC is responsible for the contents of this document.
Note: Throughout the SFPUC FAQs regarding chloramine, the term chloramine refers to one of its species, monochloramine. Where it is important to distinguish between other species (i.e., dichloramine and trichloramine), the specific terms are used. Monochloramine is the dominant species found in SFPUC drinking water while dichloramine and trichloramine would be undetectable under the treatment conditions used.