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Water Rate Cost-of-Service Study Section 4. Cost-of-Service Analysis HF&H Consultants, LLC | July 8, 2025 | Page 31 of 53 requirements to varying degrees. The existing capacity of the City’s pressure system assets is split almost equally between meeting fire flow and maximum day demand requirements. In contrast, storage capacity is driven largely by maximum day demand requirements. An allocation of these water system assets, which serve supply and distribution, determined that 43.7% of Program 65144 costs should be apportioned to fire protection services. Thus, $3,192,284 of the total $7,297,786 included in Program 65144 are attributable to public and private fire protection services, as shown in Figure 4-8. Figure 4-4. Allocation of Water Supply and Distribution Costs ¹Allocation of fire flow and maximum day demand calculated based on Table 6-4 in 2011 City of Redwood City Water System Master Plan. ²Allocation of fire flow and maximum day demand calculated based on Table 6-3 in 2011 City of Redwood City Water System Master Plan. The City’s fire flow demands include public fire hydrants, as well as private fire services. Public fire hydrants provide a benefit to all customers that is recovered through a fixed service component of all service charges calculated. Whereas, private fire services only serve the need of the specific customer account. Thus, Fire protection costs from Program 65144 were further divided among public and private protection according to the demand reserved in the system. The diameter of each fire service line was converted to a demand factor, a procedure identified in the AWWA M1 manual, 7th edition. As stated in this reference, “the demand factor is shown to bring the various connection sizes into equivalence. Using the principles of the Hazen-Willians equation for flow through pressure conduits, the relative flow potential for various size pipes is dependent on the diameter raised to the 2.63 power.” All public fire hydrants were assumed to have a 6-inch connection. Demand factors for each size service were then multiplied by the number of connections of each size to derive the total number of equivalent connections. Based on Figure 4-5, 19.3% of the fire-protection costs should be allocated to private fire service. This allocation is also included in Figure 4-7 as O&M Water Supply & Distribution (Fire Protection). Asset Values of Value Fire Flow Max Day Type Assets Allocation Demand¹ Demand² Pressure¹ $9,701,974 77% 52% 48% Storage² $2,827,336 23% 16% 84% $12,529,310 100% Allocation of Water Distribution 43.7% 56.3% ATTY/RESO.0109/CC RESO WATER RATES - EXHIBIT A REV: 11-05-25 MI