Mobility and Infrastructure Committee
March 12, 2026

2/26/2026
1 RiversideCA.gov1
RiversideCA.gov
TOTAL DISSOLVED SOLIDS (TDS) MANAGEMENT PLAN AGREEMENT BETWEEN THE CITY OF RIVERSIDE AND RUBIDOUX COMMUNITY SERVICES DISTRICTMobility and Infrastructure CommitteeMarch 12, 2026Public Works Department RiversideCA.gov2
Treatment Plant BACKGROUND
WQCP services 93,000 customers within the City of Riverside and provides treatment services for Edgemont, Jurupa and Rubidoux Community Services Districts and the unincorporated community of Highgrove.28Million gallonsper day averageBACKGROUND 2/26/2026
2 RiversideCA.gov3
•RWQCP removes organic and inorganic matter from the waste stream to ensure compliance with water quality standards before discharging to the Santa Ana River or reusing it as recycled water.•Water quality requirements are outlined under the National Pollutant Discharge Elimination System (NPDES) No. CA 0105350, Order No. R8-2013-0016.•Effluent Total Dissolved Solids (TDS) is set at 12-month flow weighted average not to exceed 650 mg/l.•RWQCP remains compliant with all NPDES effluent limitations, including the 12-month rolling average TDS of 590 mg/l.BACKGROUND RiversideCA.gov4
•Rubidoux Community Service District (RCSD), under various agreements dating back to 1978, has acquired 3.055 MGD of treatment and disposal rights from RWQCP. Historically RCSD influent flow is 1.7 MGD with a TDS concentration of 790 mg/l.•In 2019 RCSD proposed an annexation to LAFCO for the Rio Vista Specific Plan, including 1,697 dwelling units and approximately 2.7 million square feet of light industrial facilities. The City opposed the annexation due to RCSD’s continued high TDS concentrations, pending RCSD’s TDS Management Plan completion to manage high concentrations of TDS in untreated sewage.•The project is located in the northeast quadrant of the City of Jurupa Valley, specifically west of Rubidoux Boulevard, south of the Riverside/San Bernardino county line, east of Armstrong Road and Sierra Avenue, and north of La Canada Drive. The site is approximately 1.4 miles north of I-60 and 2.5 miles south of I-10. •In February 2024, RCSD submitted its draft TDS Management Plan for review. Following multiple discussions with RWQCP, the RCSD Board of Directors approved the final TDS Management Plan in 2025.BACKGROUND 2/26/2026
3 RiversideCA.gov5
•The agreement with RCSD ensures continued compliance with RWQCP effluent limits by including triggers that RCSD must follow if effluent TDS encroaches the 650 mg/l limit, or when 750 equivalent dwelling units (EDU) are connected to sewer service:–RCSD is required to construct a physical potable water supply intertie with West Valley Water District, capable of moving 2,000 acre-feet per year of low TDS water.–If 750 EDUs are connected to sewer before the Rio Vista Project is complete, RCSD will construct the physical intertie within 12 months of the 750thEDU connection.–RCSD will purchase low TDS potable water and deliver sewer to RWQCP with TDS of 650 mg/l or lower if RWQCP reaches the 12-month TDS average of 620 mg/L or compliance trigger in future NPDES permits.–Triggering TDS Concentrations have been determined based on the current NPDES permit TDS compliance calculations and anticipated compliance calculations of a forthcoming NPDES permit.–If RCSD successfully implements groundwater treatment solutions that eliminate the need for imported water, it may discontinue purchasing water through the intertie.DISCUSSION RiversideCA.gov6
RWQCP commitments include:- Notify LAFCO within thirty (30) calendar days of the execution of this Agreement that the City of Riverside has approved RCSD’s TDS Management Plan and no longer objects to annexations of the new service areas currently proposed.- Provide RCSD with prompt written notice if and/or when RWQCP discharge reaches the Triggering TDS Concentrations, as defined in the Agreement. DISCUSSION 2/26/2026
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That the Mobility and Infrastructure Committee:1. Receive and file an update on the TDS Management PlanAgreement between the Regional Water Quality Control Plantand Rubidoux Community Services District; and2. Recommend that the City Council approve the TDSManagement Plan Agreement between the City of Riverside,Regional Water Quality Control Plant and Rubidoux CommunityServices District.RECOMMENDATIONS