IEUA clears CEQA step for 9,992 AFY shift from Santa Ana River to potable reuse
Inland Empire Utilities Agency, California · Meeting date: November 4, 2026 · Published: November 5, 2026
The Inland Empire Utilities Agency board has approved an environmental addendum supporting a proposed 45% reduction in its baseline wastewater discharges to the Upper Santa Ana River watershed. The water would instead be routed to a new advanced water purification facility and stored in the Chino Basin aquifer for later potable reuse.
Key points
- IEUA approved Addendum No. 2 to the Chino Basin Program’s recirculated final PEIR and authorised filing of a Notice of Determination.
- The wastewater change proposal would divert up to 9,992 AFY from four IEUA treatment plants, a 45% reduction from baseline average annual discharges.
- IEUA would maintain at least 7,038 AFY of treated-wastewater discharges to the Upper Santa Ana River watershed above Prado Dam.
- The modified programme now identifies 27 new wells and about 19.6 miles of new conveyance pipeline, compared with 37 wells and about 30 miles assessed previously.
- The board also extended Jacobs Engineering Group’s programme-management and owner-engineering contract by $10.99 million through November 2028.
Full report
Inland Empire Utilities Agency has approved environmental documentation for a major operational shift in the Chino Basin Program: reducing effluent releases to the Santa Ana River watershed and redirecting recycled water for advanced treatment, aquifer storage and eventual potable supply.
The board unanimously approved Addendum No. 2 to the recirculated final programme environmental impact report (PEIR) on 4 November. The decision supports IEUA’s wastewater change petition to the State Water Resources Control Board, which seeks authority to redirect up to 9,992 acre-feet per year of tertiary-treated wastewater from four treatment plants to a new Advanced Water Purification Facility at Regional Water Recycling Plant No. 4.
The proposed diversion equals an approximately 45% reduction from IEUA’s baseline average annual wastewater-treatment-plant discharges to the Upper Santa Ana River watershed above Prado Dam. IEUA would continue to discharge at least 7,038 AFY of treated wastewater to the watershed, or approximately 30% of baseline average annual discharges.
The water proposed for diversion is currently discharged from Regional Water Recycling Plants Nos. 1, 4 and 5 and the Carbon Canyon Water Recycling Facility. Under the Chino Basin Program, it would receive further treatment at the AWPF before being injected into the Chino Basin aquifer for storage and later extraction as potable reuse supply within IEUA’s service area.
The programme’s planned AWPF is designed to produce 15,000 AFY of purified water from an intake of up to 17,000 AFY of tertiary recycled water, with the balance becoming reject water for disposal through IEUA’s non-reclaimable wastewater system. The plant would use membrane filtration, reverse osmosis and ultraviolet advanced oxidation.
The addendum is intended as a second-tier CEQA review required under the programme’s mitigation monitoring and reporting plan for the wastewater-diversion project. Staff said the refined infrastructure plan contains fewer facilities than were evaluated in the 2022 PEIR and that the modified project would create no new or more severe environmental effects than those assessed in the recirculated PEIR certified in July 2026.
The current engineering concept identifies 27 new wells, about 19.6 miles of new conveyance pipeline, three reservoirs totalling 2 million gallons, 10 new pump stations or booster pumps, two well-treatment units and one surge tank. The earlier programme description evaluated 37 wells, approximately 30 miles of pipeline, a single 5MG reservoir, three pump stations, five booster stations and up to three treatment systems.
The board action follows a prolonged CEQA process for the wider Chino Basin Program. IEUA certified its original PEIR in May 2022, after which the City of Ontario filed a legal challenge. A court ruling in December 2025 identified three areas requiring revision before recertification. IEUA certified a recirculated final PEIR in July 2026, while both IEUA and Ontario filed appeals after the court ruling.
Separately, the board approved a $10.99 million amendment to Jacobs Engineering Group’s programme-management and owner-engineering contract. The amendment increases the contract ceiling from $15.57 million to $26.55 million and extends the agreement through 3 November 2028. Services cover the recycled-water facilities, advanced water purification facility, purified-water conveyance, aquifer replenishment facilities and a recycled-water interconnection with the City of Rialto.
This summary was generated by AI based on the source document and may contain errors.
Source: IEUA Board of Directors Workshop Meeting - Nov 04, 2026, Inland Empire Utilities Agency