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26 <br />SEWER RATE STUDY I City of Santa Ana, CA <br />Figure 1 Mains by Installation Decade <br />Refinement of Asset Evaluation <br />Replacing assets based on a depreciation life does not address site- specific conditions that may lead to <br />increased break frequencies. Breaks may occur due to a number of reasons including age, soil <br />conditions, corrosive environments, and lack of maintenance. Unlike the Water Enterprise, the City's <br />sewer system has undergone a condition rating review by an outside vendor. <br />The City has been performing closed- circuit television (CCTV) inspections on about 70 miles of pipe each <br />year. This equates to about a 6 -7 year cycle to cover the entire system. <br />The GIS database includes information compiled from CCTV inspections over the years. About 78 <br />percent of the sewer system includes at least some inspection - related data. This information is very <br />useful in that it provides the most accurate assessment of the facilities current (recent) condition and <br />expectation for failure. The CCTV data also provides key indications related to ongoing operational / <br />maintenance considerations. In general, the City has used these observations to identify sections of <br />sewer to line or clean. However, the City has not used this information to assess the overall probability <br />and consequence of failure. <br />Having the latest CCTV inspection results are critical in assessing current pipeline conditions. Some of <br />the CCTV observation data includes indications of pipeline problems, such as structural issues and <br />grease or root issues. Of the structure issues listed, about 13 percent of all pipes in the collection system <br />have at least one location that is broken, cracked, fractured, or has a hole or offset. Almost 29 percent <br />of the pipe records are listed as having no structural defects. The remaining 58 percent had no structural <br />issues value (not inspected or no recorded value). <br />For grease, over 53 percent of all system lines are shown as being clean, about 29 percent have light <br />grease, and only about 3 percent are listed at medium or heavy. The remaining 15 percent had no <br />grease issue value. Roots show a similar status: 63 percent at none, 21 percent at light, and about 1 <br />percent are listed at medium or heavy. The remaining 15 percent had no roots issue value. <br />65B -185 <br />NOVEMBER 2014 <br />