California Assembly Bill AB557

California 2025-2026 Regular Session

• Introduced: 2/12/25
• Refer: 3/24/25
• Report Pass: 3/24/25
• Refer: 3/25/25
• Report Pass: 4/24/25
• Refer: 4/24/25
• Refer: 4/28/25
• Refer: 5/21/25
• Report Pass: 5/23/25
• Engrossed: 6/2/25
• Refer: 6/3/25
• Refer: 6/11/25

Caption

An act to amend Sections 19980, 19981, 19991, 19991.2, 19991.3, 19992, 19993, 19995, and 19997 of, to add Section 19970.5 to, to repeal Sections 19975.1 and 19991.1 of, and to repeal and add Section 19975 of, Section 19980 the Health and Safety Code, relating to housing.

Summary

AB 557 would expand California’s Factory-Built Housing Law to cover not only factory-built housing units, but also “factory-built developments” — projects in which at least 50% of the residential square footage is made up of factory-built housing. The bill would require these developments, beginning January 1, 2026, to bear an insignia of approval from the Department of Housing and Community Development (HCD), and it would extend existing state approval, inspection, and enforcement rules to the new development category. The bill also streamlines the approval process for factory-built housing plans and specifications. It allows approved plans to be identified by unit serial number and reused in later projects, including in later building code cycles if the relevant standards have not changed. HCD and design approval agencies would be required to limit review to only the portions of a plan that have not already been approved. In addition, licensed architects could approve plans and specifications under penalty of perjury, with those approvals treated as equivalent to department approval. AB 557 would shift some responsibilities away from local governments and toward the state. It repeals provisions tied to local inspection/enforcement roles and authorizes HCD to regulate installation inspection agencies for both factory-built housing and factory-built developments. The bill also preserves local authority over zoning, setbacks, fire zones, and architectural/aesthetic requirements, while stating that local requirements for factory-built housing or developments may not vary substantially from those imposed on other residential buildings of similar size. The bill would also expand penalties and enforcement tools. Violations of the factory-built housing law or related standards would remain misdemeanors, and the department could assess civil penalties for certain violations, including those involving bad faith, conflicts of interest, repeat violations, or harm to seniors, veterans, or people with disabilities. The measure declares that these changes are a matter of statewide concern and therefore apply to all cities, including charter cities. Overall, the sentiment reflected in the available voting history is strongly supportive and noncontroversial: the bill passed committee and the Assembly floor unanimously, with no recorded nay votes. The main policy tension appears to be between state-level streamlining and local control, since the bill reduces local inspection and plan-review roles while preserving only limited local land-use authority. The bill’s findings frame the changes as a housing-supply and cost-reduction measure intended to speed production of factory-built housing amid the state’s housing shortage.

Impact

AB 557 would amend multiple sections of the Health and Safety Code governing the California Factory-Built Housing Law, primarily by adding a new category of regulated project, “factory-built development,” and by expanding HCD’s oversight to include approval and inspection of those developments. It would repeal and replace provisions related to installation inspection agencies, authorize architects to perform plan approvals, create unit-serial-number-based plan reuse, and revise enforcement and penalty provisions. The bill would also limit local government involvement in plan submittal and inspection for covered projects, while preserving specified local zoning and site-development authority.

Sentiment

The bill appears to have broad support in the legislative process reflected here. It advanced through committee and passed the Assembly floor unanimously, suggesting agreement with its housing-production and streamlining goals. The bill’s stated purpose—reducing approval and inspection barriers to lower costs and timelines for factory-built housing—aligns with a generally favorable policy climate around housing supply measures.

Contention

The principal point of contention is the balance between state preemption and local control. AB 557 removes local inspection and enforcement duties for factory-built housing and extends state oversight to factory-built developments, which may concern local governments that prefer to retain more review authority. At the same time, the bill preserves local zoning, setback, fire-zone, and aesthetic review powers, indicating an attempt to limit the scope of preemption. Another potential issue is the use of licensed architects and private installation inspection agencies in place of traditional department review, which could raise questions about oversight, conflicts of interest, and consistency in enforcement, though no recorded opposition appears in the available votes.