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Show B. Only three systems surveyed had ongoing leak detection programs. Unaccounted- for water in these systems ranged from 15 percent to less than 1 percent. All of the systems have aggressive meter repair and replacement programs. C. Average leak repair cost was $ 1,171. D. One utility has abandoned its full- time leak detection program as being not cost- effective. Instead it has implemented a program of pipe replacement as a more cost- effective means of reducing water loss. The current practice among surveyed water utilities in Utah appears to be locating and fixing leaks in distribution mains when water reaches the ground surface and can be seen. Efforts to locate leaks before they surface and cause damage to roadways or other property do not seem to be widespread. In the three cases where there are leak detection programs, they did not notice any significant reduction in unaccounted- for water as a result of the leak detection program. Most water utilities will monitor leak frequency and replace pipelines that have a significant leak history. Cost Effectiveness Probably the most significant finding of the survey was the difference in the values of the water saved and the cost to repair a leak. One utility reported spending an additional $ 100,000 per year locating leaks before they surface. The most expensive cost for water reported was $ 332 per acre- foot. At this cost, at least 3.5 acre- feet of water would need to be saved to make it cost- effective to find and repair a leak. Most M& I water costs in Utah are much less expensive than $ 332 per acre- foot, so the cost savings would be much less. Most utilities have found it far more cost- effective to prevent leaks rather than find and repair. The most common means of preventing leaks is to properly install new pipelines and replace existing pipelines as they begin to experience leakage. Properly installed pipelines will not experience leaks as long as the pipe material is structurally sound. Standards adopted by local water utilities should include " trigger points" defining at what levels of unaccounted- for water will initiate water loss reduction programs by the utility such as meter repair and calibration, leak detection and repairs, and pipeline replacement. The greatest difficulty in deciding the effectiveness of a leak detection and repair program is determining the amount of water saved. However, from the survey of Utah utilities and reviewed literature, the following conclusions can be drawn: • Leaks resulting from corroded or damaged pipe develop quickly and will likely be visible from the surface. • The cost to locate and repair most small leaks is greater than the value of the water saved. The primary motivation of most utilities for reducing leaks is to minimize the potential liability from damage caused by a large leak. • Leak prevention has proven to save more water at a lower cost than an active leak detection and repair program ( if the purpose of the leak detection program is to locate the leak before it becomes visible from the surface). ^ 52 |