Foster City gets final‑stage update on San Mateo joint wastewater plant; modest cost increases noted

City staff and project representatives told the board on March 16 that San Mateo’s regional wastewater treatment plant expansion — a joint Clean Water Program in which Foster City participates — is in its performance‑testing phase and approaching completion.

A project presenter said the seeding of the plant with microorganisms was completed Dec. 23 and that performance testing began in January to verify the new processes meet regulatory and operational requirements. “That seeding happened, started on December 15 and was completed on December 23,” the presenter said. The total project estimate for the combined San Mateo/Foster City work was shown at about $603.4 million.

Staff reported roughly $5.9 million in increases since the previous quarterly update, composed of $1.8 million in contractor time‑impact requests, $1.34 million for a force‑main tie‑in that must be redone due to an incorrect location in the headworks, and about $2.7 million in additional construction‑management and program‑management costs owing to the extension of the schedule. The presenter said Foster City’s share of the net increase is approximately $1 million and that, at present, the additional amounts would not require water/wastewater rate increases.

Council members pressed staff about responsibility for the time‑impact claims and the larger program‑management increase; staff said some claims are the contractor’s and some stem from design coordination issues, and that San Mateo, which holds the contract, manages negotiations and pays bills with Foster City reimbursing its share.

Staff said the treatment‑plant processes should be operational by March performance‑test completion and that conversion work and closeout tasks will continue through May–June 2026, with IAP/AMC items wrapping later in 2026. The board received and accepted the quarterly update.