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Show A program of leak detection and repair that provides for the inspection of all conveyance and distribution mains, and the performance of repairs, at intervals of three years or less. Public Law 102- 575, Subsection 207( f)( 2)( C) Background Over 880,000 miles of distribution piping are estimated to be operating in the U. S. Water loss from leakage in the distribution systems varies depending on the materials, age and condition of the lines. Leaks generally occur in one of two ways. Improper construction can result in leaks occurring at joints, and corrosion can lead to pipe damage severe enough to cause leaks. Corrosion caused leaks are the most common form of leakage in water pipelines. The major factors contributing to corrosion leak protection include pipe composition, age, construction practices, soil conditions, corrosion conditions, external loadings and weather. Metallic pipes are subject to pitting type corrosion from corrosive soils or water. Initially, the leak does not result in significant water loss ( possibly as low as one gallon per day). As the corroded area begins to leak, however, water may increase the corrosivity of the location resulting in greater corrosion rates. In addition, the jetting action from water pressure causes increased erosion and abrasion on the reduced remaining pipe wall. Within a few days to a few months the leak will rapidly grow in size and water losses will increase. Because of the rapid rate at which the hole grows within the pit, location of the leak typically is detected as water reaches the ground surface. Design and construction practices for water pipe installation have evolved over the past century and the existing inventory of water mains in service reflects the trends in water system development, pipe longevity and specific materials in use. A summary existing types of pipe materials in operation is given in Table 1. Table 2 is a summary of the historical trends in pipe installation. The relative age of most distribution and conveyance pipe systems in Utah is young compared to the rest of the U. S. Materials generally consist of steel, ductile iron, and PVC pipe. The relatively young age of much of the material in Utah indicated that leakage should be lower in comparison to the rest of the country. Most of the growth in water systems has occurred in the past 45 years. For example, the water districts that service the west side of Salt Lake County ( Granger- Hunter, Taylorsville- Bennion, Kearns) have all been formed since 1960. The Salt Lake County Water Conservancy District was formed in 1951. A recent inventory of Salt Lake City's water system in the unincorporated area of Salt Lake County shows that approximately 28 percent of the system was installed before 1960. Seventy- two percent of this system is less than 35 years old. Utah's greatest population growth has occurred since 1960, with 50 percent of the state's population being added since that time. The net result is Utah's water systems are relatively new and still in good condition. |
