Updating the New York City Water System

The New York City Bureau of Water Supply maintains extensive records of all water main breaks dating back at least as far as 1940. A computerized file of the main break records was prepared to allow rapid evaluation. A computerized inventory of the distribution mains, according to year of installation and pipe diameter, was also prepared in order to allow main breaks to be related to length of main in a particular category. These data are used to calculate break rates. The statistical analysis of main break records indicated that year of installation, pipe diameter, and month of occurrence were important factors in main breaks. A recommended 10-year water main replacement program has been developed for Brooklyn using break rates and hydraulic capacity as the criteria.