THINKING: housing
Narrow but Mighty AB 507: California’s New Adaptive Reuse Law
AB 507, California’s landmark law effective July 1, 2026, expands the range of buildings and sites eligible for “by right” residential adaptive reuse while reducing development costs and project requirements as incentives.
What Makes AB 507 Different From Earlier Adaptive Reuse Laws?
While perhaps limited in its specific use case, AB 507 offers all encompassing solutions pioneered by previous California legislation to make more homes cheaper and faster.
AB 1490 enabled adaptive reuse streamlining, but with stringent affordability requirements. AB 2011 also offered approval shortcuts with similar high affordability rates, but only to applicable commercial sites with zero envelope protections. Building off of the downtown San Francisco revitalization program created by AB 2488, AB 507 now allows cities and counties throughout California to establish their own tax incentive financing initiative for adaptive reuse residential projects.
Does your building qualify?
| Location | Age | Zoning / use | Scope | Labor Standards*** | Affordability Requirement Minimums**** | |
|---|---|---|---|---|---|---|
• Urbanized area per US census bureau • Less than 20 acres • 75% of perimeter adjoins parcels with developed urban uses | < 50 years* | • Any zoning • No immediate prior industrial use • If mixed use, non-residential use to be compatible with existing zoning • No hotels, unless inactive for at least 5 years | • Must create housing or in mixed-use projects, at least 50% of square footage is housing • Can include an additional new construction building on site** | • Prevailing Wage • Apprentices • Health care expenditures for each employee | 8% very low income, 5% extremely low income Or 15% for lower income | Owner-occupied housing: 30% moderate income Or 15% for lower income |
* If older than 50 years, the site must first be evaluated for historical significance.
** The new structure must comply with SB 35 and either AB 2011 or SB 6 for streamlining. Parking exemptions and impact fee reductions under AB 507 only apply to the adaptive reuse portion of the project.
*** Additional requirements apply for projects with more than 50 units or buildings over 85’ in height.
**** If a local jurisdiction has affordability requirements, the development will need to comply with the more stringent percentages.
What’s streamlined?
Typically, any change of land use or zoning necessitates the local jurisdiction’s discretionary approval – which ultimately could be denied even after months of CEQA reviews, community evaluations and subjective design reviews. Now under AB507, residential adaptive reuse conversions are treated as “by right” projects. As a result, plans are evaluated against established criteria and altogether bypass any subjective public hearings. As long as the drawings comply with all of the objective standards and codes, the jurisdiction cannot unfairly withhold approval.
How Long Does AB 507 Approval Take?
AB 507 also starts two key countdowns. Local governments have, at most, 90 days to approve a project deemed compliant by the planning director and, 90 days to notify applicants of noncompliance with objective standards. For projects with less than 150 units, the shot clock is reduced to 60 days.
Envelope & parking protections
In an effort to entice investors, AB 507 creates two key benefits: envelope protection and a parking exemption.
A local government shall not impose any local development standard on any project that is an adaptive reuse project pursuant to this article that would require alteration of the existing building envelope, except if required by any applicable local building code
Parking is not required for the portion of a project consisting of a building subject to adaptive reuse that does not have existing onsite parking.
With these provisions, buildings that would have otherwise been ruled out by their physical restraints can start to pencil out.
For an additional new construction building on site, parking requirements may not exceed 1 space per unit. Parking can be completely exempted for the ground-up development if the parcel is located within one-half mile of public transit, or within a historic district.
Lower Development Fees & Affordability Requirements
Because non-residential parcels do not have an established density, developers can take advantage of density bonuses by choosing their base density.
A developer proposes converting a 4 story office building on an otherwise empty lot, into 100 rental units. 100 units becomes the parcel’s base density. To qualify for AB507 streamlining, the developer then allocates 8 units to very low income rates and 5 units to extremely low income. If she then designates 44 units of the office conversion to moderate income rates, the project is eligible for a 50% density bonus and 3 concessions under AB2345. At the parcel’s undeveloped area, up to 50 additional units can be created in a new ground-up development.
Historic Bonus
At historic sites, one of AB 507’s compliance pathways requires developers to sign an affidavit to comply with the US Secretary of the Interior’s Standards for Rehabilitation. As this is the same key standard to apply for Federal Historic Tax Credits, it’s more than worth it for builders to submit applications to the State Historic Preservation Office and National Park Service.
AB 507 takes a well rounded approach to a specific project type. Developers experienced with adaptive reuse and knowledgeable of the bill’s limits and incentives can maximize this development niche. With San Francisco office vacancy rates nearing 30% and ever increasing construction costs due to tariffs, it’s never been a better time to find a creative way to build more housing in existing buildings.
Designing for the next conversion
How can architects design buildings that evolve with its city’s needs by preparing for multiple life cycles? At a basic level, a modular structural grid and tall ceiling heights can provide program flexibility. Projects built with environmental site specific principles can establish a high baseline for thermal comfort, and if needed at a later date, mechanical systems can supplement. And simple good design basics that prioritize light, greenery and open space can promote an occupant’s satisfaction, regardless of the exact program.
Next Steps for Developers
To cash in on AB 507’s streamlined approvals, scope concessions and financial incentives, developers should first should take these three steps:
- Assess Applicability: Does your site meet the baseline criteria outlined? Verify against the specified site requirements to prevent any hiccups later on.
- Review Local Jurisdiction’s Standards: Check with your municipal to confirm affordability rates and understand any applicable objective design standards
- Partner with Experts: Experienced Architects and Land Use Attorneys can help decode project limitations and layer multiple incentives
Bridging the gap between evaluating a site's potential and executing a fully compliant conversion requires specialized expertise. Reach out to our team today for a preliminary feasibility assessment of your office building or commercial real estate portfolio.