AB 6 charges the Department of Housing and Community Development (HCD) with convening a cross-agency working group to research whether residential developments of between 3 and 10 units can be designed and constructed under the California Residential Code (CRC) and what modifications would be necessary to maintain health and safety. If the working group recommends changes, HCD and participating state agencies must develop and consider proposed building standards for adoption into the statewide code.
Separately, the bill requires HCD to study how new and existing building standards affect construction costs for single-family and multifamily housing and to perform recurring reviews with the explicit goal of reducing construction costs for new residential development. The measure creates a formal interagency process to explore a simpler compliance path for small multifamily projects while directing HCD to quantify cost impacts and pursue standards changes aimed at lowering those costs.
At a Glance
What It Does
Directs HCD to assemble a multiagency working group to evaluate allowing 3–10 unit residential developments to follow the California Residential Code and to assess related health and safety modifications. Separately requires HCD to report on construction cost pressures from building standards and to undertake periodic reviews intended to lower those costs.
Who It Affects
Small multifamily developers and builders who target 3–10 unit projects, local building departments and code officials who review those projects, and state agencies that set and enforce building standards (e.g., Building Standards Commission, State Fire Marshal, Division of the State Architect, Energy Commission). Architects, engineers, and component manufacturers would also be affected if the CRC pathway changes design and product requirements.
Why It Matters
The bill creates a vehicle for potentially reclassifying small multifamily work into a residential code pathway that is typically simpler than commercial/multifamily provisions, which could shorten design cycles and lower costs. It also institutionalizes cost-impact analysis and a recurring review process—tools that can shape how future code changes balance safety, energy, and affordability.
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What This Bill Actually Does
The bill adds two sections to the Health and Safety Code. The first section requires HCD to convene a working group that includes the California Building Standards Commission, the State Fire Marshal, the Division of the State Architect, the Energy Commission, and other stakeholders to study whether developments of between 3 and 10 units can safely be designed and constructed under the California Residential Code (the state's adoption of the International Residential Code).
The working group’s task is to identify what amendments or targeted modifications to state building standards would be necessary to allow that shift while maintaining health and safety.
HCD must collect the participating agencies’ input and produce a findings report to the Legislature. If the working group recommends changes, HCD and the agencies with authority to propose building standards must research, develop, and consider proposals for adoption by the California Building Standards Commission during the next applicable triennial code update.
Importantly, the bill explicitly authorizes HCD to exceed the conventional scope and application of the International Residential Code where needed to create a compliant pathway for 3–10 unit projects under the California Residential Code.The bill also makes clear that several existing specialized codes remain applicable to residential occupancies of any size: the California Electrical, Mechanical, Plumbing, and Energy Codes. And it restricts the working group from proposing expansion of the state Residential Code by re-adopting International Residential Code chapters that the state omitted in the 2025 CRC because they duplicated other parts of the California Building Standards Code.Separately, HCD must perform a review of construction cost pressures that building standards impose on single-family and multifamily housing, report those findings to the Legislature, and then repeat that review on a recurring three‑year cycle tied to the triennial code update process.
The recurring review carries an explicit objective: to revise or update standards as needed with the aim of reducing the cost of new residential construction by 30 percent. The statutory text assigns HCD the central research, coordination, and proposal role, while leaving actual adoption decisions to the Building Standards Commission and the usual rulemaking channels.
The Five Things You Need to Know
HCD must convene a multiagency working group to study permitting 3–10 unit residential developments under the California Residential Code and to identify any necessary health and safety modifications.
If the working group recommends changes, HCD and participating agencies are directed to research and consider proposed building standards for submission to the California Building Standards Commission for the next triennial code update.
The statute explicitly allows HCD to exceed the conventional scope of the International Residential Code to enable the CRC pathway for 3–10 unit projects, giving HCD latitude to draft nonstandard scope changes.
HCD must conduct an initial review of construction cost pressures tied to building standards and then perform the same review every three years, with the stated goal of reducing the cost of new residential construction by 30 percent.
The bill preserves the application of the California Electrical, Mechanical, Plumbing, and Energy Codes to residential occupancies of any size and prohibits the working group from reintroducing IRC chapters that were omitted from the 2025 California Residential Code due to duplication.
Section-by-Section Breakdown
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Working group convened and membership
This subsection requires HCD to convene a working group that must include the Building Standards Commission, State Fire Marshal, Division of the State Architect, Energy Commission, and other stakeholders. The provision sets the working group's research mission: identify and recommend amendments allowing 3–10 unit residential developments to be designed and constructed under the California Residential Code, and identify any health and safety modifications each participating entity must evaluate within its expertise.
Reporting and pathway to propose code changes
HCD must compile the working group’s findings into a one-time report to the Legislature; if the group recommends code amendments, HCD and the agencies with proposal authority must research and develop proposed standards for the Building Standards Commission’s consideration at the next triennial update. Mechanically, this delegates early-stage drafting and interagency coordination to HCD while preserving formal adoption authority with the Commission and the established rulemaking process.
Scope limits and retained code applications
The statute clarifies two limits: it does not change the applicability of Parts 3–6 (Electrical, Mechanical, Plumbing, Energy)—those remain applicable to residential occupancies regardless of size—and it forbids the working group from proposing to expand the CRC by reintroducing IRC chapters that the state omitted in the 2025 CRC because they duplicated other California code parts. That narrows reform to targeted amendments rather than wholesale re-adoption of omitted IRC material.
Initial review of construction cost pressures
HCD must perform a targeted review of how new and existing building standards affect construction costs for single-family and multifamily housing and deliver its findings to the Legislature. The review is structured around the causal link between standards and cost drivers—materials, labor, prescribed systems, and compliance processes—so policymakers get evidence linking specific standards to price impacts.
Recurring reviews and a 30% cost-reduction objective
Beginning with the next triennial code update referenced in the statute and continuing every three years, HCD must repeat the cost-pressure review to revise or update standards 'as needed' with an explicit goal of cutting the cost of new residential construction by 30 percent. This provision moves cost-considerations into the regular code review rhythm and creates a quantitative policy target to guide standard revisions.
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Explore Housing in Codify Search →Who Benefits and Who Bears the Cost
Every bill creates winners and losers. Here's who stands to gain and who bears the cost.
Who Benefits
- Small multifamily developers and owner-builders: If the CRC pathway is adopted, these developers could use simpler residential code provisions for 3–10 unit projects, potentially shortening design times and lowering permitting complexity.
- Prospective renters and buyers in small multifamily properties: Reduced construction costs could translate into more supply or lower price pressure for units typically under 10 apartments.
- Manufacturers of standardized components and modular builders: A residential-code pathway often favors repeatable designs and standardized products, creating market opportunities for offsite construction and pre‑fabricated systems.
- Local jurisdictions aiming to increase housing stock: Faster review and clearer technical paths for small multifamily can improve permit throughput and help meet housing targets.
- HCD and participating state agencies: The bill formalizes HCD’s coordinating role on housing standards, increasing its influence over future code changes and giving agencies a structured venue to shape technical trade-offs.
Who Bears the Cost
- State agencies and technical staff: The Building Standards Commission, State Fire Marshal, DSA, Energy Commission and HCD will incur staff time and analytic burden to participate, research, and draft proposed standards without specified funding in the statute.
- Local building departments and code enforcement: New or revised standards require training, updates to plan-check processes, and possibly more complex compliance checks during a transition to a CRC pathway.
- Design professionals (architects and engineers): A new compliance pathway will require translating code changes into practice, revising standard details, and potentially reworking approved templates—costs that may be borne up front by designers.
- Manufacturers and subcontractors who supply specialty systems: If standards change to allow different systems or omit certain requirements, some suppliers may need to retool products or face reduced demand for specialized equipment.
- Builders potentially exposed to mixed interpretations: During any transitional period, inconsistent local interpretation of new CRC-based standards could increase legal and schedule risk for contractors.
Key Issues
The Core Tension
The bill pits affordability and speed—lowering construction costs and simplifying compliance for 3–10 unit projects—against the equally legitimate need to preserve life‑safety, energy, and accessibility protections; crafting standards that materially reduce costs without creating safety gaps is the central, unresolved trade-off.
The bill threads two policy goals—simpler compliance for small multifamily and a measurable reduction in construction costs—into the technical code process, but that combination creates implementation frictions. Translating 'allowing' 3–10 unit projects into concrete, safe standards requires granular trade-offs: which structural, fire‑safety, accessibility, and energy provisions can be relaxed or retooled without raising risk?
The statute preserves the applicability of specialized codes (electrical, mechanical, plumbing, energy), so any CRC pathway will have to integrate those codes’ requirements with modified residential provisions, which is technically complex and may blunt expected cost savings.
The recurring cost‑review requirement and the 30 percent reduction target supply a sharp policy aim but little methodological guidance. Measuring the causal effect of individual standards on total construction cost is analytically difficult: costs reflect market factors (materials, labor, land, financing) as well as code requirements.
Without defined metrics, baseline methodologies, or funding for rigorous economic analysis, the 30 percent objective risks becoming an aspirational benchmark rather than an evidence‑driven target. Finally, the statute centralizes early drafting with HCD but leaves adoption with the Building Standards Commission; successful implementation will depend on durable interagency agreement, adequate staffing, and a willingness by the Commission to adopt potentially controversial scope changes.
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