FOR IMMEDIATE RELEASE05-14
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.