UCLA‑led wastewater needs assessment finishes Phase 1; Phase 2 will map inadequate systems and estimate costs through 2027

State Water Resources Control Board staff and the UCLA project team told the board on July 16 that Phase 1 of the statewide wastewater needs assessment — funded by a 2022 contract — is complete and that Phase 2 will run through 2027 to deliver mapped lists of systems of concern, solution options and cost estimates.

"UCLA is the lead investigator and they subcontracted four other universities for specialized tasks," Danielle Jimerson, senior engineer leading the board’s side of the project, told the board. The board approved a multi‑year contract with UCLA for $4,000,000 in 2022, she said.

Why it matters: The assessment aims to surface where sanitation infrastructure fails or risks failure — including treatment plants, collection systems and unsewered parcels — and to estimate the technical solutions and public funding needed to remedy those gaps across California.

Phase 1 accomplishments and scope: The project completed an inventory and initial data methods in Phase 1 (July 2023–June 30, 2025). Staff said the phase defined categories for three permit‑type system groups (NPDES, waste discharge requirements or WDR, and collection systems under the sanitary sewer order), built a baseline survey, began a field campaign to ground‑truth on‑site systems and started to develop quantitative criteria for “inadequacy” and for “risk of inadequacy.” The team reported an initial roster of about 2,657 systems across the three permit types that will be evaluated in Phase 2.

Greg Pierce, principal investigator for the UCLA team, said Phase 1 also established a framework to assess on‑site septic systems county‑by‑parcel using predictive models developed by the University of Massachusetts to identify likely on‑site systems where public sewer does not serve parcels. "We are using a predictive model to identify likely locations of on‑site wastewater systems," Pierce said.

Board members asked whether under‑enrollment in regional permitting could hide collection systems from the inventory. Project staff said some collection systems and on‑site systems are indeed imperfectly represented in state databases and that regional boards and office of enforcement have been helping fill gaps: “There are under 50 systems that…have failed to reenroll in the new sanitary order,” a regional enforcement representative told the board, noting ongoing digitization and county reporting work to improve coverage.

Modeling solutions and costs: Sacramento State’s Office of Water Programs is leading the cost‑and‑solution side and will use Phase 1 methods to model technical fixes and produce high‑level cost estimates for systems the assessment deems inadequate. Pierce emphasized these will be statewide, high‑level estimates that do not replace project‑level engineering reports. The team will include operation and maintenance costs, technical assistance and multipliers to better approximate real‑world project costs.

On on‑site systems, UMass will run parcel‑level models to identify likely septic or on‑site wastewater systems and then feed those results into a groundwater‑impact assessment focused on nitrate risk — a pathway the team said could be used to prioritize support and connection planning.

Equity and outreach: Pierce and staff said the project includes an advisory group of diverse stakeholders, a commitment to prioritize underserved and disadvantaged communities in risk scoring, and a field campaign led by UC ANR that includes community input. Several board members and advisory‑group speakers urged that the assessment include interim supports for low‑income households on on‑site systems (pumping, emergency assistance) and that the team consider rate surveys and other affordability metrics to guide funding prioritization.

Next steps: Phase 2 tasks include running the empirical risk and inadequacy assessments across the system lists, modeling recommended technical solutions, estimating capital and ongoing costs, and identifying likely funding sources and gaps. The project team plans a public mapping tool and expects to publish interim reports and advisory‑group materials through 2027.

Ending: Board members said they expect to use Phase 2 outputs to guide funding, regulatory enrollment and targeted technical assistance and asked the project team to continue iterative refinement of the methods and to coordinate closely with regional boards and the Division of Financial Assistance.