San Mateo County, CA Cap Rates by Neighborhood

County-Wide Gross Yield: The Number That Misleads

The county-wide gross yield sits at 2.83%, computed from a median rent of $3,760/month against a median home price of $1,595,764. That figure is arithmetically correct and analytically almost useless.

A 2.83% gross yield describes a blend of asset types, price tiers, and neighborhoods across a county where a $2.0M single-family home in Burlingame and a rent-controlled unit in East Palo Alto both fold into the average. Subtract property taxes, insurance, maintenance, and vacancy and you arrive at a net operating yield well below 2% for most stabilized acquisitions. This is not a cash-flow market. The data confirms it.

The reason to own here is price appreciation, not income. San Mateo County prices rose about 7% year-over-year in October 2025, with the highest closed-sale count since spring 2022. A 1.67% ZHVI-reported annual gain undercounts that momentum at the upper end, where luxury sales above $5 million hit their highest October count on record. The spread that matters is not county-wide yield versus a benchmark. It is the yield difference across asset segments and sub-markets, because that spread tells you where marginal capital is better deployed.

Asset Segment Breakdown

The brief does not supply neighborhood-level rent data by zip code, but it does provide a clear picture across three distinct segments: single-family residential, condominiums, and ADU-augmented value-add. Each carries a different implied yield profile.

Single-Family Residential

Median SFR prices reached about $2.0M in May 2025 in San Mateo County, down from a $2.3M mid-2024 peak. At $3,760/month median rent, the gross yield on a $2.0M SFR is about 2.26% before any operating costs. Net of the 1% general property tax levy alone (about $20,000/year on a $2.0M home), the net cap rate drops below 1.25% assuming a typical expense load.

The SFR segment has outperformed condos on price. It is the better equity vehicle, not the better income vehicle. Inventory is structurally constrained: fewer than 12 to 15 homes sell per month in Burlingame, and 2023 through 2025 were the three lowest sales-volume years in the past 25 years. Scarcity alone supports further price appreciation, compressing yields further over the hold period.

Condominiums

Condo median prices fell about 4.5% year-over-year in October 2025, creating a relative entry-price advantage. If a condo priced at $950,000 to $1,100,000 can rent near the county median of $3,760/month, the gross yield range climbs to about 4.1% to 4.7%. That is the most income-competitive entry point the brief identifies.

The risk is that condo pricing has moved down while SFR pricing held or recovered. Price softness can reflect either a buying opportunity or a structural demand shift. The county's high-cash-buyer concentration (about 30% all-cash in Burlingame and Hillsborough) skews toward single-family, so condos attract more rate-sensitive, leveraged buyers, which partly explains the divergence.

ADU-Augmented Single-Family

ADUs are eligible across all R-1, R-2, and R-3 zones with no minimum lot size and no owner-occupancy requirement. Units under 750 square feet are exempt from impact fees. On a $1.6M median-priced lot, adding a 700-square-foot ADU at market rents of $2,500 to $3,000/month could add 1.9% to 2.3% in gross yield on that slice of capital. Total blended yields on the combined parcel would still not breach 3.5% gross, but ADU addition is the most accessible yield enhancement strategy for existing SFR owners in this market.

Neighborhood-Level Yield Adjustment

The brief supports enough named geography to draw directional distinctions, though not a full comparable table with per-neighborhood median rents.

Property Tax Impact on Net Cap Rate

San Mateo County collected $4.1 billion in property taxes in FY 2024-25, up 6% year-over-year. The countywide 1% general levy totaled $3.3 billion. On a representative acquisition at the median price of $1,595,764, the base levy is about $15,958/year. Special charges and debt service add proportionally; total effective tax rates on new purchases commonly reach 1.15% to 1.25% all-in, putting annual tax carry at $18,350 to $19,950 on a median-priced property.

Annual gross rental income on that same property at $3,760/month is $45,120. Property taxes alone consume 41% to 44% of gross rental income before management, maintenance, insurance, or vacancy. The net cap rate on a median-priced, unencumbered acquisition is not 2.83%; it is in the range of 1.0% to 1.5% depending on expense assumptions. Leveraged investors underwriting this market should expect negative or near-zero cash-on-cash returns at current purchase prices and rates.

Flood Insurance Adjustment to Net Yield

For Bay-side properties that remain in FEMA Special Flood Hazard Areas, flood insurance costs reach $6,000 to $7,000/year. On a property generating $45,120 in gross annual rent, that expense alone takes another 13% to 15% off gross income, pushing net yield below 1% even before debt service.

The October 2024 FEMA map revision removed a real number of North Shoreview and North Central San Mateo parcels from SFHA designation, eliminating mandatory flood insurance for those properties. For investors targeting San Mateo city specifically, confirming SFHA status on a parcel-by-parcel basis can represent a net yield improvement of 130 to 155 basis points annually versus an equivalent property still inside the flood zone.

Redwood Shores parcels retain Bay-side exposure. Buyers there should obtain current FEMA flood zone determinations before pricing the deal.

Cap Rate Outlook

Yields in San Mateo County are more likely to compress than expand over the next 12 to 24 months, for four reasons rooted in the brief data.

First, AI-sector liquidity events are translating directly into buyer demand in the $3M to $5M range, with OpenAI employees alone representing close to $10 billion in secondary-market stock monetization. That capital seeks Peninsula real estate before it seeks any other asset class.

Second, the updated Housing Element adopted March 2025 and the new Development Code (Title 8, October 2024) are rezoning parcels for higher-density multifamily, but new supply takes 3 to 7 years to deliver at scale. Rezoning creates future development opportunity; it does not relieve near-term inventory pressure.

Third, electrified Caltrain with four peak trains per hour per direction and 25-minute faster SF-to-SJ express service increases the rental premium commanded by walkable station-area properties across the county. Station-adjacent rents should widen against car-dependent properties over time.

Fourth, supply is historically scarce. Months of supply at 0.86 in January 2025, homes selling in a median of 14 days, and 2023 to 2025 being the three lowest sales-volume years in a quarter century: all of these point to price appreciation outrunning rent growth, which means gross yields continue to erode.

The one segment where yield expansion is plausible is condominiums, where prices have already pulled back 4.5% year-over-year while rents have held. If that price softness persists, condo gross yields in the 4% to 5% range become a more defensible entry point than the SFR segment.

Model your specific deal with our investment property calculator to stress-test NOI against flood insurance, property tax, and AB 1482 rent-cap scenarios before committing to a sub-market.