Office-to-Housing Conversion in Downtown San Francisco

Where a conversion pencils downtown

San Francisco publishes a floor count for every parcel, so this page counts floors from the city’s own Assessor records instead of estimating them from height.

191 of the 205 office buildings screened in the downtown C-3 districts score at least 50, meaning the model rates them worth a professional feasibility study. The median building has 89% of its floor area within daylight reach and a deepest interior point 49 feet from a window, and 10 are past the 80-foot threshold where conversion needs a carved light well.

The model values a converted home at $366K, roughly the average price per unit of San Francisco apartment buildings of five or more units sold in the first quarter of 2026. It also charges a seismic upgrade on every building. San Francisco requires one when walls, partitions or ceilings change on two-thirds or more of a building’s floors, and a full conversion changes all of them. None of the city’s own conversion incentives below is in these numbers. The packet planner adds them one at a time.

The city’s building heights come from a 2010 LiDAR survey, so they serve here only as a check on the Assessor’s floor counts. 4 buildings went up after the survey; they keep the Assessor’s count and say so on their page. 27 buildings that already stood in 2010 are withheld, because the height the survey recorded for them, or the lack of one, cannot hold the floor count the roll gives them. That usually means the count belongs to a taller building on the same parcel.

Why most office buildings can never become apartments

The binding constraint on office-to-residential conversion is floor-plate geometry, not financing. Apartments need light and air; office floors were built deep on purpose.

This is why a subsidy program alone does not produce conversions, and why a list of vacant buildings is not a pipeline. Information was never the bottleneck — cities have published vacancy reports for years. The bottleneck is that establishing which specific buildings are physically convertible is expensive expert work, and most of them are not.

The 92 buildings a RESIDE grant would unlock, if they qualify

Each of these fails on financing rather than geometry: the floor plate works, the pro-forma does not, and a grant closes the difference. None has been checked against the law’s vacant-and-abandoned test, which public GIS data cannot show. Buildings are ranked by conversion suitability score.

“Gap” is conversion cost minus completed value before any subsidy. “Grant” is the modeled RESIDE award. Where the grant exceeds the gap, the formula is over-funding the project — see the finding above. All 205 screened buildings, including those that do not pencil, are in the survey above and in the full list by address, each linked to its own analysis.

What a RESIDE appropriation would buy in Downtown San Francisco

Congress has not funded the program. If it does, how HUD sizes each award matters as much as the amount.

For each funding level, the table shows the most of the 92 buildings above that the money could close, taking the lowest cost per home first: once with awards at the modeled formula, and once with each award sized to the building’s actual financing gap. Funding all 92 would take $488.8M under the formula and $207.6M sized to the gap.

These are upper bounds for one study area, not forecasts. Any appropriation is national and competitive across every eligible state and city, and HUD’s priorities are not modeled. The law’s $1 million minimum award, which applies in a year with at least $100 million, is not applied here. Every building would still have to meet the law’s vacant-and-abandoned test, and homes are valued at market rate although RESIDE housing must be mostly affordable, which would widen every gap.

What San Francisco is already doing

San Francisco has layered three incentives on downtown conversions. Since March 2025, conversions in the C-3 districts and part of C-2 owe no development impact fees and no inclusionary housing requirement, on the first 7 million square feet to be approved. The city estimated those costs at $70,000 to $90,000 per home. Since voters approved Proposition C in March 2024, the first sale after a conversion pays no real property transfer tax, which is 6% of a sale price of $25 million or more. That applies to conversions before 2030, on up to 5 million square feet. And since February 12, 2026, the Downtown Revitalization Financing District can pay an enrolled conversion an annual incentive for up to 30 years from the property-tax growth it creates, with enrollment open through 2032.

California law adds a fourth. Since July 1, 2026, the Office to Housing Conversion Act (AB 507) lets qualifying conversions proceed by right and exempt from CEQA, in exchange for affordable homes and labor standards.

The pipeline is still small. Emerald Fund and SDG have filed plans to convert the vacant six-story office building at 150 Hayes Street into 104 apartments, and it is among the buildings screened here. San Francisco’s office vacancy rate was 29.2% in the second quarter of 2026, according to CBRE, and 205 buildings being screened does not mean 205 buildings are empty.

Downtown San Francisco lies in California's 11th Congressional District. Nancy Pelosi, who has represented San Francisco in the House since 1987, is not running in 2026: Scott Wiener and Connie Chan advanced from the June 2, 2026 top-two primary to the November 3 general election, so the district's member of Congress will change in January 2027.

What the RESIDE Act, Section 210 of the ROAD to Housing Act, funds

The RESIDE Act is law, but it has no money yet, its grants go to cities rather than developers, and only vacant and abandoned buildings qualify. All three facts are widely misreported.

The Revitalizing Empty Structures Into Desirable Environments Act was introduced as H.R. 5591 in the 119th Congress and enacted as Section 210 of the 21st Century ROAD to Housing Act, which became law without the President’s signature on July 11, 2026. It authorizes HUD to run a pilot program, in fiscal years 2027 through 2031, of competitive grants to convert vacant and abandoned buildings into attainable housing, with priority for economically distressed communities, Opportunity Zones, needs in a city’s consolidated plan, and cities that have passed ordinances easing conversion.

Most empty offices would not qualify. The law covers only a vacant and abandoned building: one built for commercial or industrial use that code enforcement has found unsafe, with no corrective action 90 days after the owner was notified, or that is in court-ordered receivership or nuisance abatement, or is abandoned under state law. This survey cannot see code enforcement or court records, so a building shown as unlocked by RESIDE here is one that would pencil with a modeled grant if it qualified. The homes must also be attainable, serving households up to 120% of area median income with most units affordable at 60%, while this model values every home at market completed value, so its grant results are optimistic.

Individual awards are capped at $10.0M, and eligible applicants are HOME participating jurisdictions — states and local governments — not private developers or building owners. That changes what this tool is for. It is not a developer’s capital stack; it is a worksheet for the grant application a city would file, and for the question of which buildings would justify the ask.

Because HUD has not published a Notice of Funding Opportunity, the award formula used here — 30% of eligible conversion cost, capped at $60K per home and $10.0M per award — is modeled on how comparable HUD gap-financing programs are structured. The $10.0M per-award cap is statutory. The rest is an assumption, and 96 of the 205 buildings here hit that statutory ceiling.

More on the law: The ROAD to Housing Act explained · Environmental review changes · CDBG and HOME changes · Opportunity Zones · The Innovation Fund · The Build Now Act · Manufactured housing and the chassis rule · Chassis-free manufactured homes by state · How RESIDE grants should be sized · The ban on large investors buying homes

State law for San Francisco: Office to Housing Conversion Act (AB 507) · New California housing laws for 2027

How this was computed, and what it cannot tell you

Every figure on this page is reproducible from public data. Stating the limits is part of the method, not a disclaimer attached to it.

Building footprints with heights from a 2010 LiDAR survey, zoning, parcels, addresses and streets come from DataSF, and use, floor counts and year built from the San Francisco Assessor-Recorder's 2025 secured roll. Footprints are projected to a local tangent plane in feet, eroded inward by 35 feet to separate daylit band from dead core, and the largest circle that fits inside each footprint gives the distance from the deepest interior point to the nearest facade. Unit yield is the daylit band times a 80% circulation factor divided by a 750 sq ft average home, across every floor above the ground floor. Cost is a base of $260/sq ft plus itemized change-of-occupancy triggers — plumbing risers, seismic retrofit, operable windows, egress stairs, sprinklers — weighed against completed value, then against the modeled grant.

Two further figures appear on each building’s own page. Window line is the building’s exterior wall summed across its residential floors and divided by the homes estimated in it: daylight efficiency says how much of a floor is near glass, and window line says whether there is enough glass to go round, since every bedroom needs one. Plate shape is the isoperimetric quotient — 1.00 for a circle, about 0.79 for a square, lower for anything longer or more articulated. The direction that favours housing is the opposite of the one that favours offices: a compact plan is the cheapest envelope per square foot to build and heat, while apartments are sold by the window, so the notched outline an office would call wasteful is the one that converts.

For Downtown San Francisco the model replaces 2 defaults with local figures. Completed value per home is $366K: the average price per unit of San Francisco apartment buildings of five or more units sold in the first quarter of 2026, from NorCal MLS Alliance sales (Morgan Thomas, 2026-10-12). The seismic retrofit allowance is $45 per sq ft: San Francisco requires a building's lateral system to meet current code at reduced forces when walls, partitions or ceilings are altered on two-thirds or more of its floors, which a full office-to-residential conversion does (San Francisco Department of Building Inspection, 2026-10-12).

The geometry math is validated against shapes with known analytic answers, and computed floor areas agree with the city’s own recorded areas to within 0.01%, which confirms the coordinate projection. The browser model that powers the interactive survey above is checked against the Python engine on every build; both must agree on units, cost, grant, gap, tier and score for all 205 buildings.

Questions

Cite or reuse this analysis

Everything on this page is free to quote, republish and build on, with credit. The scored dataset behind it is one download.

The text and dataset are licensed under CC BY 4.0: copy, adapt and republish them, commercially or not, with credit and a link back. Footprints, heights and zoning come from the City and County of San Francisco, whose own terms still apply to that source data. See the terms of use.

Sources

1. San Francisco's office vacancy rate was 29.2% in the second quarter of 2026, down from 34.7% a year earlier and from an all-time high of 36.9% in the third quarter of 2024. CBRE Research, “San Francisco Office Figures, Q2 2026” — verified 2026-10-12.
2. Emerald Fund and SDG have filed plans to convert 150 Hayes Street, a vacant six-story 1968 office building in Civic Center, into 104 apartments. The San Francisco Standard, “SF office-to-housing conversion at 150 Hayes” — verified 2026-10-12.
3. San Francisco apartment buildings of five or more units sold for roughly $366,000 per unit on average in the first quarter of 2026, on sales reported to the NorCal MLS Alliance. Morgan Thomas, “San Francisco Apartment Building Market Report, April 2026” — verified 2026-10-12.
4. Ordinance No. 20-25, passed March 4, 2025, waives development impact fees, including the inclusionary housing requirement, for conversions of non-residential space other than hotels to housing in the C-3 districts and part of C-2, on the first 7,000,000 square feet to receive final approval. A project that does not get a building permit within five years of approval forfeits the waiver. San Francisco Board of Supervisors, “Ordinance No. 20-25 (File No. 240927)” — verified 2026-10-12.
5. The city estimated that impact fees and inclusionary requirements typically add $70,000 to $90,000 per unit to the cost of a downtown office-to-housing conversion. Office of the Mayor, City and County of San Francisco, “Mayor Breed Proposes Eliminating Office to Housing Conversion Fees” — verified 2026-10-12.
6. Proposition C, approved March 5, 2024, exempts the first sale after a commercial-to-residential conversion from the real property transfer tax, for conversions before 2030 and up to 5,000,000 square feet. The tax is 5.5% of a sale price from $10M to $25M and 6% at $25M or more. City and County of San Francisco, Office of the Controller, “Real Estate Transfer Tax Exemption and Office Space Allocation: Economic Impact Report” — verified 2026-10-12.
7. The Downtown Revitalization Financing District, effective February 12, 2026 under AB 2488 (2024), pays enrolled conversions an annual incentive for up to 30 years from the property-tax growth they create. Projects can enroll through 2032. Office of the Mayor, City and County of San Francisco, “Mayor Lurie Signs Legislation to Accelerate Downtown Housing Creation” — verified 2026-10-12.
8. The RESIDE Act is Section 210 of the 21st Century ROAD to Housing Act (Public Law 119-101), which became law without the President's signature on July 11, 2026. Section 210 authorizes a HUD pilot program, in fiscal years 2027 through 2031 and subject to appropriations, of competitive grants to HOME participating jurisdictions to convert vacant and abandoned buildings into attainable housing; in a year at least $100M is available, each grant is $1M to $10M. U.S. Government Publishing Office, “Public Law 119-101, 21st Century ROAD to Housing Act” — verified 2026-09-14.
9. As of September 9, 2026, HUD had issued no Notice of Funding Opportunity, guidance or rule for the RESIDE pilot, and no funds had been appropriated for it. Bipartisan Policy Center, “21st Century ROAD to Housing Act Implementation Tracker” — verified 2026-09-14.
10. The RESIDE Act was introduced as H.R. 5591 in the 119th Congress. As introduced, it would have funded the program with up to $100M a year of HOME appropriations above $1.35B; the enacted law does not. Congress.gov, “H.R.5591 — RESIDE Act” — verified 2026-09-14.
11. Every building screened in Downtown San Francisco lies in California's 11th Congressional District, checked building by building against the 120th Congress district boundaries. U.S. Census Bureau, “TIGERweb Legislative Map Service: 120th Congressional Districts” — verified 2026-10-12.
12. Building footprints with 2010 LiDAR heights, zoning districts, parcels, addresses and street centerlines come from DataSF, and use, floor counts and year built from the Assessor-Recorder's 2025 secured roll. City and County of San Francisco, “DataSF: Building Footprints, Zoning Districts, Parcels, Enterprise Addressing System, Streets, Assessor Historical Secured Property Tax Rolls” — verified 2026-10-12.
13. Completed value per home is $366K: the average price per unit of San Francisco apartment buildings of five or more units sold in the first quarter of 2026, from NorCal MLS Alliance sales. Morgan Thomas, “San Francisco Apartment Building Market Report, April 2026” — verified 2026-10-12.
14. The seismic retrofit allowance is $45 per sq ft: San Francisco requires a building's lateral system to meet current code at reduced forces when walls, partitions or ceilings are altered on two-thirds or more of its floors, which a full office-to-residential conversion does. San Francisco Department of Building Inspection, “Information Sheet G-29, Adaptive Reuse, draft of July 2, 2024 (San Francisco Existing Building Code 503.11.1)” — verified 2026-10-12.

The scored dataset behind this page is available as GeoJSON. Findings generated 2026-10-12 from DataSF (Building Footprints, Zoning Districts, Parcels, Enterprise Addressing System, Streets) and the San Francisco Assessor-Recorder's 2025 secured roll.