demands, so projected demand and supplies are equivalent in past UWMPs. If included non-potable, untreated values would be between an additional 1,500 – 3,000 AF per year.
Service Area Demands with Water Use Efficiency
The service area demands shown in Table B-1 represent the total retail water demands for IRWD’s service area including municipal and industrial demands, agricultural demands, recycled, and others. These demand types and the modeling methodologies used to calculate projections from 2030 to 2045 are described in Section 4 of the 2025 UWMP. It should be noted that service area demands projected for 2030 through 2045 decrease from service area demands for 2025 due to an update in the demand forecast used in the 2025 UWMP from the 2020 UWMP.
Non-Potable Water Demands
The non-potable water demands shown in Table B-1 represent demands for recycled water only; however, IRWD also serves non-potable water (untreated water) including water for irrigation and surface reservoir storage. Due to variations in UWMP non-potable (untreated) data tables in the past, only recycled water was included for consistency in Reduced Reliance on the Delta projections and methodology. Per the Guidebook Appendix C, non-potable supplies may have a demand hardening effect due to the inability to shift non-potable supplies to meet potable water demands. When WUE or conservation measures are implemented, they fall mainly on the potable water users.
Potable Water Demands
Calculated potable water demands are determined by subtracting non-potable water demands from total service area demands in the DWR provided tables. These values are consistent with the recorded data in each UWMP data source for non-potable and total water demands.
Total Service Area Population
IRWD’s total service area population as shown in Table B-1 was generated by the Center for Demographic Research (CDR) at California State Fullerton, with actuals (2010, 2015, 2020 and 2025 from each respective UWMP) and projections further described in Section 3 of the 2025 IRWD UWMP for years 2030 to 2045.
Water Use Efficiency Since Baseline
The WUE numbers shown in Table B-1 represent IRWD’s calculated increase in WUE over time, consistent with the approach in Appendix C of the UWMP Guidebook.
Appendix B - 7
IRWD – 2025 Urban Water Management Plan – Reduced Delta Reliance
Powered by FlippingBook