Agenda - 06-12-2007-3d - Laserfiche WebLink

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((~ OWASA fiscal years, FY 96-97 (July 1, 1995 through June 30, 1997). Single Family Detached -Average water use for each of the five size groups (fmished area) of the single family detached class were derived from the FY 96-97 water use data presented in Exhibit 1. These groupings were selected to optimize several considerations. Each class spans an equal size range of 700 square feet. The upper and lower-most size classes (less than 1701 and greater than 3800 square feet) represent substantial differences in size and value, yet contain sufficient sample data to support a credible statistical pattern. Finally, the size class with the largest number of new homes (2401 to 3100 square feet) represents the midrange of both the fmished area and water use variables; i.e., the mean values of this range are nearly identical to the average values of the entire sample set. Multi-Family Individually Metered -Average water use (127 gpd) for this class was obtained from OWASA customer billing records, as described in notes to Exhibit 3. Non-Residential 5/8-Inch Meter Accounts -Actual account data for this class were not analyzed for FY 96-97. The reported annual (322 gpd) and winter (302 gpd) averages were obtained by adjusting the observed annual and winter FY 95 non-residential 5/8-inch account averages (334 gpd and 313 gpd, respectively) in proportion to the reduction from 200 gpd to 193 observed in annual use for the single family residential class between the FY 95 and the FY 96-97 sampling periods. Examples: Annual average = 334 gpd x 193/200 = 322 gpd. Winter average = 313 gpd x 193/200 = 302 gpd. The resulting availability fees calculated for non-residential 5/8-inch accounts are the basis for all other non-residential fees, which were scaled up by meter capacity ratios, as in the previous rate structure, and as recommended by in the recent OWASA rate study~i~. Water Loss and Peaking Factors The need for backbone water system capacity is a function of short term (peak) customer demands and longer term demands represented by losses from the system. The loss factor of 1.08 applied to the average day demands of all user classes reflects OWASA's actual unaccounted-for loss of eight percent of total fmished water production. The recent rate study report applied one-day peaking factors of 2.0, 1.4, and 1.5, to the average day demands of single family detached, multi-family individually metered, and non- residential 5/8-inch accounts, respectively, in its analysis of backbone capacity needs~r~. OWASA's present analysis incorporated modifications to the single family peaking factor in order to reflect actual summertime differences observed among the size classes, as described below. Single Family Detached -Peaking factors highlighted with gray shading in Column 7 of Exhibit 3 were derived by normalizing the average summer demands of each fmished area size class to the summer average (248 gpd) of the entire single family detached class as a whole, to which the recent rate study had assigned a peaking factor of 2.0. For example, the peaking factor of 1.3 applied to the <1701 square foot subclass was obtained by multiplying 4