65B - PROPOSED WATER AND SEWER RATE ADJ

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City of Santa Ana, CA I WATER RATE STUDY Table B - 9: Summary of PoF Criteria used in this Analysis PoF Criteria Weight Comment Strategy / Assumption Cohort Rank (0- 60% Assigned values 0 -5 Cohort 5, High PoF Score: 1970s / 1980s Ductile Iron Pipe and High 5 values) range, multiply by 2 Pressure 36" MWD Transmission Line to get values 0 to 10 Cohort 4, Med -High PoF Score: Asbestos Cement Pipe installed before 1940 Cohort 3, Med PoF Score: Cast Iron Pipe installed before 1960 Cohort 2, Med -Low PoF Score: Cast Iron Pipe Installed after 1960 Cohort 1, Low PoF Score: Asbestos Cement Pipe Installed after 1940 Cohort 0, Very Low PoF Score: All other pipe materials and installation years Pipe Vintage 40% Assigned values Pipes installed before 1940 were assigned a score of 10 (age) based on assumption Pipes installed in 1940 or after were assigned a decreasing linear score that older pipes are from 10 to 1 more likely to fail 1970s and 1980s Ductile Pipe was considered 0 percent Repeated n/a Additive: based on 2 or more previous failures: add 2 to final PoF score Failures assumption that if a 1 previous failure: add 1 to final PoF score pipe fails once, there is a higher probability Never failed: keep final PoF score that it will fail again Total (sum of 100% The resulting PoF above) I I scores are 0 to 10. By applying the weighting described above (60% Cohort Score, 40% Age, and 0% Failures) to each of the 21,477 active main pipeline segments in the Santa Ana Water System, a 0 to 10 PoF Score was calculated for each and the distribution is shown in Figure B - 27 below. Figure B - 28 provides a map of water mains color coded by total PoF score. BLACK & VEATCH I Appendix B: Water CIP Prioritization erocess 65B -125 113