Buying a Home in San Mateo County, CA: Transfer Tax, Coastal Zone & Jumbo Loans
The City of San Mateo's own conveyance tax is a genuine outlier — most of the rest of the county is standard.
San Mateo County stretches from the Peninsula tech corridor (Redwood City, San Mateo, Menlo Park) to the rural Pacific coastline around Half Moon Bay and Pescadero. It combines Silicon Valley-adjacent tech-buyer dynamics with a genuinely tiered, and in one city quite high, transfer tax structure, plus coastal-zone rules on the county's west side.
What’s the transfer tax in San Mateo County?
The county base is the standard $1.10 per $1,000, but the City of San Mateo adds its own steep tiered conveyance tax that pushes the combined total to $6.10 per $1,000 for most residential sales.
Most cities — including Redwood City, Menlo Park, and Half Moon Bay — charge only the standard rate with no separate city add-on. The City of San Mateo is the exception: following the passage of Measure CC (November 2022), it imposes a tiered conveyance tax on top of the county rate — $5.00 per $1,000 for consideration under $10 million, rising to $15.00 per $1,000 at $10 million or more. Combined with the county rate, that's $6.10 per $1,000 for a typical residential sale in the City of San Mateo, and $16.10 per $1,000 for the rare $10M+ transaction. Confirm any other specific city's rate directly before estimating closing costs.
What permitting rules apply on the San Mateo County coast?
The western, coastal side of the county — Half Moon Bay, Montara, Moss Beach, Pescadero, and the unincorporated coastside — falls under the California Coastal Act and a certified Local Coastal Program.
Development in the mapped coastal zone — new construction, additions, and many remodels — typically requires a Coastal Development Permit in addition to standard building permits. This area also carries a long-standing slow-growth, agriculturally-oriented land-use tradition distinct from the built-up Peninsula side of the county — confirm zoning and coastal-zone boundary status with the county Planning and Building Department before assuming standard-Peninsula permitting timelines apply.
How does the tech job market affect Peninsula home buying here?
San Mateo County's Peninsula cities (Redwood City, San Mateo, Menlo Park, Burlingame) see a buyer pool heavily influenced by nearby tech employment.
RSU vesting schedules and liquidity events (IPOs, acquisitions) can drive noticeable seasonal demand swings, and jumbo-loan financing is the norm rather than the exception for most single-family purchases in these cities.
What about commute options and financing limits across the county?
San Mateo County sits along the Caltrain corridor connecting San Francisco to the South Bay, and the 2026 conforming loan limit here is $1,249,125 — the highest FHFA cost tier.
Caltrain makes San Mateo the more traditionally transit-oriented of the Bay Area satellite counties for a Peninsula tech commute, though specific current schedule and electrification details should be confirmed directly with Caltrain for a time-sensitive decision — don't assume a property is transit-connected without checking actual walking distance to a station. Any loan above the $1,249,125 conforming limit requires jumbo financing, which is common rather than exceptional given local prices. The statewide ADU baseline (Government Code §65852.2) applies countywide, but individual cities layer on their own permit fees and design standards — verify at the specific city level.
Disclosure landscape
- Confirm the City of San Mateo's Measure CC conveyance tax tier before estimating closing costs — it substantially exceeds the standard statewide rate.
- Coastal Development Permit requirements apply to new construction, additions, and many remodels on the coastside — verify with the county Planning and Building Department.
- Current Caltrain schedule and service levels should be confirmed directly for any commute-dependent purchase decision.
Frequently asked
Why is San Mateo transfer tax so much higher in some areas?
The City of San Mateo passed Measure CC in November 2022, adding its own tiered conveyance tax on top of the standard county rate — $5.00 per $1,000 for sales under $10 million, bringing the combined total to $6.10 per $1,000. Most other cities in the county, like Redwood City and Half Moon Bay, charge only the standard $1.10 per $1,000.
Can I build or remodel on the Half Moon Bay coastside without extra permits?
Probably not without an added step. Property in the mapped coastal zone typically requires a Coastal Development Permit in addition to standard building permits — confirm zone status with the county Planning Department before assuming a standard timeline.
Will I need a jumbo loan to buy in San Mateo County?
Likely, given local prices. The 2026 conforming loan limit is $1,249,125, and jumbo financing is the norm rather than the exception for most single-family purchases in the county's Peninsula cities.
This is educational guidance, not legal advice. Consult a California real estate attorney for legal questions specific to your transaction.