$1,298,000
641 Waltermire St, Belmont 94002
Size check
The listing's square footage against the county assessor's record and the permits on file.
The listing and the county record agree within 10%.
What can explain a difference
- Space built without a permit.
- Permitted work the assessor has not recorded yet.
- An ADU, a finished basement or a converted garage counted in one figure and not the other.
- Different measuring. Listing agents and the assessor often measure the same house differently.
Our Belmont permit record starts in 2026. Work permitted before then will not appear above.
AddressIntel AI Briefing
The optimal play here is stealth density: primary + ADU + JADU to capitalize on the high ADU feasibility, though the local liquefaction hazard acts as a significant cost-escalating blocker for foundation work. While the 1939 bungalow is updated, its tiny 878 sqft footprint on a nearly 4k sqft lot offers excellent long-term development value once mitigation costs are priced in.
Property Permit History
Recent Neighborhood Remodeling (Belmont)
Parcel & Zoning Info
ADU Potential
Flag / irregular · ~92 ft frontage × 95 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.
Seller Motivation
Inferred from days on market and listing-description language (e.g. "as-is", "estate sale", "motivated seller"). A screening heuristic for likely negotiability, not a statement about the seller's circumstances.
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 1,574 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. City sets no explicit FAR (or is not individually curated); allowable area is a conservative estimate. Source: Belmont Zoning Ordinance 4.2.3(d) Table 5 (Lot Size/Intensity) as a CAP on the default estimate; Table 4 slope FAR NOT applied, no per-parcel slope available (as of 2026-09-03). 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
Nesbit Elementary
Belmont-Redwood Shores Elementary
Tierra Linda Middle
San Carlos Elementary
Design Tech 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
67/100
Based on recent sales velocity and local demand in 94002.
Flippability Score
58/100
Measures neighborhood renovation density vs. recent permits on this property.
Bidding War Prob.
46%
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 Belmont (94002): $1,350/sqft, plus 5% because new houses sold at a median 1.07x their comps across 239 real rebuilds. Sized within 25% of the 1,600 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.
Interest on the purchase price for the whole project plus half the build budget, since construction draws ramp up. The default is 7% over 33 months, the median purchase-to-sale time of 239 real Peninsula and South Bay rebuilds. Set the rate to 0 for a cash purchase, or use your own lender's terms.
Projected Profit
Warning: Project is mathematically underwater.
Recent Comparables (Belmont 94002)
Sized to the modelled 1,600 sqft build: sales within 25% of it. Smaller houses sell for more per foot, so pricing a rebuild off them overstates resale.