Newsletter Sign-up Printer Friendly Format Translate This Page Text Size Small Medium Large


April 14, 2005

Contact: Charles G. Sturcken (718) 595-6600

New York City Department of Environmental Protection Information Statement About Water Main Breaks

New York City’s water distribution system consists of a grid network of over 6,600 miles of pipe, over 100,000 fire hydrants connected to the piping for fire fighting and thousands of valves to control the flow of water and pipe joints that clasp the piping in place.

The system experiences between 550 and 650 water main breaks annually. The overwhelming majority of them are very small and cause little disruption. They are easily and quickly repaired. Water main breaks may take the form of pipe breakage, broken connections to a water main from a fire hydrant, and leaks in valves or pipe joints. To make repairs, water flowing through the main must be shut off by DEP to allow the ruptured area to be excavated and the exact site of the break located and repaired. This often results in disruption of water service to neighborhood business and residents along the line of the pipe. On occasion there are alternative water main feeds to locations, and they may experience low water pressure rather than total cessation of water service.

There are a number of factors that can cause water main breaks or system failures. It is difficult to ascertain their immediate causes. It has been noted that the majority of main breaks take place during seasonal changes – fall/winter, winter/spring, and thus temperature extremes may play a role. In addition to weather, traffic, utility contractors, and scheduled upgrades of the system can all cause unintentioned ruptures. There is a forensic application that can determine the reason for a break, but the process takes from a week to ten days, by which time the repair has been completed.

Approximately 7% of the water mains are over 100 years old. Some 2,200 miles of pipe were laid before 1930 and are unlined cast iron; between 1930 and 1969 about 2,400 miles of cement lined cast iron pipes were installed. Pipe laid after 1970 is cement-lined ductile iron and comprises about 1,600 miles of the distribution system

The City replaces approximately 60 miles of water mains annually at a capital cost of 100 million dollars. In addition, as a preventive measure, crews investigate the City’s entire distribution network via an electronic leak detection program. DEP crews complete the electronic sounding cycle every three years, locating and repairing small leaks before they make their way to the surface.


More Information

NYC Department of Environmental Protection
Public Affairs

59-17 Junction Boulevard
19th Floor
Flushing, NY 11373

(718) 595-6600