San Mateo Public Works staff and consultants presented a comprehensive update to the city's Storm Drain Master Plan at the Jan. 14 Sustainability and Infrastructure Commission meeting, describing system condition assessments, hydraulic modeling, a prioritized capital improvement program (CIP) and funding options.

James Yang, senior engineer at Public Works, said the plan reassesses a system designed decades ago and incorporates recent extreme storms (2022–23 atmospheric rivers), updated condition inspections and integrated hydraulic modeling. Consultant Justin Maynard (Schaff & Wheeler) described fieldwork including CCTV inspections of selected pipes, visits to nine of the city's 10 pump stations, and a system model covering roughly 150 miles of pipe and 15 miles of channels.

Staff reported estimated capital needs of approximately $233,000,000 under their current CIP list; integrating climate‑change stress tests raised that estimate by about $34,000,000 (total roughly $267,000,000). Marina Lagoon pump station upgrades were singled out as the largest single item at approximately $121,000,000. The stormwater fee (approved by property owners in 2023 and implemented in FY2024–25) currently generates about $4,000,000 annually; staff said the fee provides a stable base but is not sufficient to fund all recommended improvements.

Staff asked the commission for feedback on three policy choices: (1) whether to continue allocating a modest portion of the stormwater fee (staff proposed about $250,000 per year) to address neighborhood nuisance ponding projects; (2) whether the master plan should support strengthening private development stormwater requirements; and (3) general commentary on the draft CIP and project priorities. Commissioners widely supported retaining some funding for neighborhood ponding projects as an important "maintenance and trust‑building" measure and urged aggressive pursuit of bonding and grant strategies to accelerate larger projects. Several commissioners stressed that while nuisance ponding projects are lower on CIP priority lists, addressing visible, day‑to‑day flooding maintains public confidence while the city pursues large, multi‑agency shoreline and lagoon projects.

Consultants described climate stress testing using CalAdapt precipitation projections and state OPC sea‑level guidance (intermediate sea‑level estimates used for 2050 and 2100 scenarios). Modeling results indicate many CIP projects would be effective through 2050 but additional projects or upsizing may be required for 2100 conditions.

Staff indicated the draft master plan is planned for public release in late February 2026, with two community engagement meetings in spring 2026, return to the commission and city council for consideration and a target for formal adoption by June 2026. Staff said they will continue refining the CIP and pursuing grant and financing strategies.

No formal action was taken; staff will incorporate commission feedback into recommendations to city council.