$1,728,000
621 E 16th Ave, San Mateo 94402
AddressIntel AI Briefing
The optimal strategy is an SB 9 lot split into multiple units to exploit the low lot coverage and significant price-to-ARV discrepancy. Developers must design around liquefaction risks during foundation engineering. Demographics show high owner-occupancy, suggesting a strong resale market for newly built high-density housing.
Property Permit History
Recent Neighborhood Remodeling (San Mateo)
Parcel & Zoning Info
ADU Potential
Flag / irregular · Corner lot · ~96 ft frontage × 101 ft deep, a tucked-away rear unit is very private; access is typically via the pole driveway. A second street frontage lets an ADU take its own entrance and address.
Screening heuristic based on lot size, existing coverage, lot orientation, and hazard overlays. CA ADU law is ministerial statewide; verify max size, setbacks, and JADU owner-occupancy with the local planning dept.
Redevelopment Potential
SB 79 preempts the limit these figures are measured against. This parcel sits within a half mile of a qualifying transit stop in a city that adopted the state standards, so state law overrides the local height and density caps and the governing envelope is a multifamily one, substantially larger than the city's single-family allowance. Read the score, class and headroom above as describing the municipal rule only, not this parcel's ceiling. Confirm the city's adopted SB 79 implementation before underwriting.
Meaningful unused floor-area headroom under current zoning, room to add square footage. The city’s single-family rule allows roughly 2,250 sqft of gross floor area on this lot.
Screening estimate comparing existing living area to the city's single-family floor-area limit, which SB 79 preempts on this parcel. FAR figure is a discretionary-review trigger, not a hard cap. Treat as approximate. Source: San Mateo Muni Code 27.18.060 (R1-B/C default; district unresolved) (as of 2026-08-24). Verify FAR, coverage, setbacks, and height with the local planning dept.
Hazard Snapshot
Flood Zone
Fire Severity
Liquefaction
Fault Zone
Not a substitute for a Natural Hazard Disclosure (NHD) report. Zones reflect available GIS data and may not cover all localities. Liquefaction and fault flags: modified from California Geological Survey, Web Service of Official Maps of Alquist-Priolo Earthquake Fault Zones and Web Service of Official Maps of Seismic Hazard Zones (2025).
Nearby Public Schools
Sunnybrae Elementary
San Mateo-Foster City
Borel Middle
San Mateo-Foster City
Aragon High
San Mateo Union High
School boundaries are subject to change. Nearest school distance does not guarantee enrollment eligibility. Check with the local district. Data provided by CDE.
Proprietary Intelligence
Market Heat Index
79/100
Based on recent sales velocity and local demand in 94402.
Flippability Score
78/100
Measures neighborhood renovation density vs. recent permits on this property.
Bidding War Prob.
59%
Likelihood of multiple offers based on local list-to-sale ratios and DOM.
Proforma ROI Calculator
Back-of-the-napkin deal analysis across development strategies.
SB 79 governs this parcel. It sits within a half mile of a qualifying transit stop in a city that adopted the state standards, so state law preempts the local height and density limits and the real ceiling here is a multifamily one, well above what the city's single-family rule allows. The figures below model a detached rebuild, which is not the play on this lot — we don't quote a return on it. Check the city's adopted SB 79 implementation before you underwrite.
Median of 12 recent single-family sales in San Mateo (94402): $1,434/sqft. Sized within 25% of the 2,300 sqft build, because smaller houses sell for more per foot and pricing a rebuild off them overstates resale.
Commission, transfer tax and closing. Deducted from resale before profit, so the ROI below is net of the exit rather than gross.
Carry on total capital for the project duration. At 0% the model is a cash purchase; 12 months at a typical construction-loan rate moves ROI by 6 to 10 points on a deal this size, so price it with your real rate.
Projected Profit
Warning: Project is mathematically underwater.
Recent Comparables (San Mateo 94402)
Sized to the modelled 2,300 sqft build: sales within 25% of it. Smaller houses sell for more per foot, so pricing a rebuild off them overstates resale.