$5,495,000
408 Warren Rd, San Mateo 94402
AddressIntel AI Briefing
This historic century-old home sits on a spacious lot in a premier San Mateo neighborhood with zero hazard risks. The optimal play is an SB 9 lot split into 4 units to unlock maximum density, or alternatively a stealth density: primary + ADU + JADU setup to preserve the main home's historic character. The lack of environmental blockers and strong neighborhood demographics make this a highly versatile site.
Property Permit History
Recent Neighborhood Remodeling (San Mateo)
Parcel & Zoning Info
ADU Potential
Flag / irregular · ~135 ft frontage × 179 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 4,336 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 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.
Nearby Public Schools
San Mateo Park Elementary
San Mateo-Foster City
Crocker Middle
Hillsborough City Elementary
Burlingame 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
58/100
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 4,336 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): $1,440/sqft. Sized within 25% of the 4,300 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 4,300 sqft build: sales within 25% of it. Smaller houses sell for more per foot, so pricing a rebuild off them overstates resale.