San Mateo County assessment roll 2026: $357.6B total assessed value (4.85% YoY) — development pipeline noted

Today in 90 Seconds

San Mateo County’s Assessor has posted the 2026–27 assessment roll registering $357.6 billion in total assessed value, a 4.85% increase from the prior year. The release highlights where large projects have concentrated across the county — useful for owners, lenders, appraisers and developers updating comp sets and tax‑exposure forecasts.

What changed, in numbers

• Total assessed value: $357.6 billion
• Year‑over‑year change: +4.85%
• Cities with concentrated project activity called out in the release: Redwood City, South San Francisco, Menlo Park, Brisbane, Burlingame
• Representative recent commercial completions named in the release: Elco Yards (South Main), Bay Meadows Station 1 (San Mateo), Peninsula Innovation Point (Burlingame), Primary School campus expansion (East Palo Alto)

Why the county roll matters for Peninsula CRE

The assessor’s roll is not just a tax document. For Peninsula stakeholders it performs three practical functions:

1. Comparable inventory: the roll provides a dated, county‑level inventory of recent completions and large projects that should be reflected in transaction comp sets and market models.
2. Valuation signal: persistent assessed‑value growth (this is the sixteenth consecutive year of growth per the release) signals value retention or moderate appreciation that lenders and underwriters should weigh into cap‑rate and stress testing assumptions.
3. Tax and cashflow planning: changes in assessed value drive property tax exposures and municipal revenue forecasts that can affect operating expense assumptions and entitlement timing for new work.

How this lines up with Q2 office market trends

Q2 Peninsula office reporting shows stabilized vacancy pressure across core submarkets and offers up‑to‑date rent guidance for underwriting and leasing strategy. Together with the assessment roll, these data points help calibrate near‑term expectations for absorption, rent recovery, and repositioning opportunities.

Tactical implications for owners, investors and lenders

1. Update comp libraries: add the specific completions named in the assessor release to valuation comparables and re‑check effective dates for certificate of occupancy or recent sale/lease data.
2. Revisit tax budgets: run sensitivity scenarios for 2027 budgets using a +4–5% assessed value baseline to gauge incremental tax expense and municipal revenue impacts on cash flows.
3. Underwrite stabilization paths: where borrowers intend to lease‑up or reposition, use Q2 vacancy and rent guidance to model realistic absorption timelines and rent ramps rather than relying solely on county‑level value trends.
4. Prioritize entitlement tracking: for projects clustered in Redwood City, South San Francisco, Menlo Park, Brisbane and Burlingame, reconcile the assessor’s project list with local planning/permit filings to spot timing gaps or upside in assessed value realizations.

What We're Watching

• Local permit and certificate‑of‑occupancy filings for the projects named in the roll (Elco Yards, Bay Meadows Station 1, Peninsula Innovation Point, Primary School expansion) as confirmation of completion dates and occupancy milestones.
• City planning and entitlement updates in Redwood City, South San Francisco, Menlo Park, Brisbane and Burlingame for material changes to project schedules or scope.
• Q3 market reports and leasing snapshots for the Peninsula office market to confirm whether Q2 stabilization continues or reverses.
• Any county notifications or appeals that materially adjust 2026–27 assessed values (affecting tax bills or retroactive adjustments).

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Sources & Documents

• San Mateo County Assessor-County Clerk-Recorder & Elections (ACRE) — San Mateo County’s 2026-27 Assessment Roll Surpasses $357.6 Billion, Up 4.85%, Marking Sixteenth Consecutive Year of Growth — primary source
• Kidder Mathews — Peninsula/San Mateo Office Market Report — Q2 2026