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Show TABLE 1. Current inventory of water Pipes in Operation Type % of Total Miles in U. S. cast Iron Line 25.8 unlined 22.2 Ductile iron .•'•'•. • Lined 16.7 unlined 2.5 steel 4.0 Asbestos cement 15.1 concrete pressure 2.2 ! PVC 9.2 Other: Galvanized, copper or lead 2.2 TABLE 2. Summary of Historical Trends in Pipe installation Year of installation Dominant Pipe Characteristics pre 1900 Horizontal cast iron 1901- 1930 Pit cast, not fully supported along length of pipe, no attention to corrosivity of soils, lead caulked bell and spigot joint 1931- 1940 Centrifugal cast, bolted mechanical joint and roll- on joint cement mortar lining, pipe thickness design included internal working pressures and bedding conditions 1941- 1955 Cray cast iron, tyton joint with a rubber gasket, pipe thickness design included external loads 1955- 1990 Ductile iron post- 1990 48% Ductile iron, 39% PVC, 12% Concrete Community Impact Board and the Drinking Water Board also have financial aid programs that help water utilities replace old M& I pipelines in the state. Present practice in Utah generally is to install either PVC or ductile iron pipe. There are no data documenting precisely the quantity of various pipe materials being installed in Utah today. The trend seems to be more towards PVC The policy of most Utah utilities is to replace pipe that is beginning to leak. The older systems are systematically being replaced because it is less expensive to replace a leaking pipeline than to continue to repair it. Since 1975 the Utah Board of Water Resources has funded over 300 M& I water projects involving the replacement of old leaking or undersized M& I pipelines in the state of Utah. Other state programs such as the 46 |