San Clemente staff outline costs and risks of joining Doheny desalination project

San Clemente City staff on Thursday presented the council with details of a proposed regional desalination project at Doheny Beach and options for city participation.

The presentation described a 5 million‑gallon‑per‑day plant being advanced by South Coast Water District and noted that if San Clemente purchased 1 million gallons per day of capacity, “it would help the city in diversifying its water supply portfolio and improve reliability, especially in the event of an outage,” a staff member said. Staff said the purchase would lower the city’s reliance on imported water from about 80% to about 67% and increase stored water reliability to roughly 61 days in the modeled outage scenario.

Why it matters: staff and outside studies presented by staff framed the project as a local supply that could reduce the city’s dependence on Northern California and Colorado River imports in a prolonged outage. But the project also carries higher operating costs and energy intensity than current supplies: staff reported modeled desalination costs ranging from roughly $1,800 to $2,600 per acre‑foot in sensitivity cases compared with current Metropolitan Water District costs of about $1,200–$1,400 per acre‑foot.

Cost and rate impacts: staff said participating would raise the city’s water‑purchase budget by roughly $1 million (from about $600,000 to $1.6 million in the examples shown) and that a direct pass‑through could raise an average single‑family household’s monthly bill by roughly $1.80 to $5.00, with a mid‑case near $3.00. Staff noted that the contract would likely include CPI escalators and pass‑throughs for electricity; several council members and residents flagged uncertainty around future electricity prices as a major cost driver.

Environmental and operational concerns: staff said project permits are near completion at state and federal agencies, and that brine discharge would be released to a two‑mile ocean outfall that has been permitted. Staff also described on‑site generators and proposed solar arrays as partial mitigations for power outages but cautioned that electricity typically makes up over half of desalination operating costs.

Council and public reaction: council members questioned immediate commitment given the projected per‑acre‑foot costs and the city’s current ability to reach long outage durations through conservation and existing supplies. One council member said the city is at the “end of the pipeline” and urged more outreach to the South Coast Water District and broader public input. Residents who spoke urged caution on costs and raised groundwater and marine‑life concerns.

Next steps: staff said the project team will return with more detailed, not‑to‑exceed pricing (expected after a 60% design and market checks) and that South Coast Water District seeks an early decision on agency participation. Council members directed staff to continue engagement and to bring further analysis and community outreach before making a commitment.