$1,849,000
523 Maple St, San Mateo 94402
AddressIntel AI Briefing
The optimal play is stealth density: primary + ADU + JADU, but the existing high lot coverage of 64% and 'brand new' marketing status severely limit development options. Splitting this tight 2,880 sqft lot via SB 9 is physically and economically blocked. Investors should hold the asset as a premium rental to leverage the high local owner-occupancy demand.
Property Permit History
Recent Neighborhood Remodeling (San Mateo)
Parcel & Zoning Info
ADU Potential
Flag / irregular · ~84 ft frontage × 88 ft deep, a tucked-away rear unit is very private; access is typically via the pole driveway.
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
Existing home already uses most of the allowable floor area, little expansion headroom. Zoning allows roughly 1,440 sqft of gross floor area on this lot.
Screening estimate comparing existing living area to the city's single-family floor-area limit. 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); 6,000 sqft cap (as of 2026-06-30). 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.
Nearby Public Schools
Baywood 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
77/100
Based on recent sales velocity and local demand in 94402.
Flippability Score
60/100
Measures neighborhood renovation density vs. recent permits on this property.
Bidding War Prob.
60%
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.
Zoning allows roughly 1,840 sqft on this lot, and the default builds to that envelope. The FAR figure is a discretionary-review trigger, not a hard cap.
Median of 12 recent single-family sales in San Mateo (94402): $1,460/sqft. Sized within 25% of the 1,800 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 1,800 sqft build: sales within 25% of it. Smaller houses sell for more per foot, so pricing a rebuild off them overstates resale.