Simplified ADU Planning with AB 434 in California

Key Points:

Pre-Approved ADU Plans

By January 1, 2025, all cities and municipalities in California are required to offer a selection of pre-approved ADU plans. These plans will be accessible on city websites, allowing homeowners and property developers to browse and choose a plan that fits their needs quickly. The availability of these pre-approved plans is intended to simplify and expedite the approval process, making it more straightforward to get started on an ADU project.

Role of Architects

Architects will play a crucial role in designing these pre-approved ADU plans. The expertise and professional touch they bring to these designs ensure that the plans are not only aesthetically pleasing but also compliant with local building codes and regulations. While there may be fees associated with using these pre-approved designs, they offer a reliable starting point for homeowners. The involvement of architects in the design process can provide homeowners with a sense of reassurance about the quality and compliance of their ADU plans.

Plan Check Fees

Despite the availability of pre-approved plans, cities are allowed to charge the same fees for the “plan check” process as they would for any other set of plans. This fee structure ensures that the quality and compliance of ADU designs remain consistent across different municipalities. Homeowners should be prepared for these fees as part of the overall cost of their ADU project.

Efficiency Goals

The primary goal of AB 434 is to make the ADU planning and construction process more efficient. By providing pre-approved designs, the law aims to reduce the time and cost of creating custom ADU plans from scratch. This efficiency is particularly beneficial in addressing California’s ongoing housing crisis, allowing for quicker development of additional housing units.

Advantages of AB 434

Time and Cost Savings: One of the significant advantages of AB 434 is the potential for time and cost savings. Pre-approved ADU plans eliminate the need for lengthy design and approval processes, allowing homeowners to start their projects sooner. By using these ready-made designs, homeowners can avoid some of the expenses associated with custom architectural services and reduce the overall cost of their ADU projects. This financial security and reduced time investment can give homeowners the confidence to proceed with their ADU projects.


Making pre-approved ADU plans available on city websites enhances accessibility for homeowners and property developers. This transparency allows individuals to easily find and review various design options, making the planning process more user-friendly. Having these resources readily available online also means that homeowners can make informed decisions without consulting multiple professionals.

Standardized Quality and Compliance: The use of pre-approved ADU plans ensures a level of standardized quality and compliance with local regulations. These designs are created by qualified architects and reviewed by city officials, guaranteeing they meet all necessary building codes and safety standards. This standardization helps prevent potential issues during construction and ensures that the final ADU is functional and legally compliant.

Considerations for Homeowners

Property-Specific Adjustments

While pre-approved ADU plans provide a solid foundation, they may still require modifications to fit the unique characteristics of each property. Factors such as lot size, shape, topography, and existing structures can all influence the final design. Homeowners should be prepared to work with architects or designers to make necessary adjustments that align with their specific property conditions. This preparation and proactive approach can make homeowners feel more in control of their ADU projects.

Potential Fees

Homeowners should also know the possible fees associated with using pre-approved ADU plans. These fees can include costs for accessing the designs, making necessary modifications, and the standard plan check process. It’s essential to factor these expenses into the overall budget for the ADU project to avoid any unexpected financial surprises.

How AB 434 Supports Housing Solutions

AB 434 represents a significant step forward in addressing California’s housing challenges. By streamlining the ADU planning and construction process, the law makes it easier and more affordable for homeowners to build accessory dwelling units to their properties. This increased efficiency is expected to contribute to developing more ADUs, which can provide much-needed housing options for families, elderly relatives, and renters.

Addressing Housing Shortages

California has long faced a housing shortage, particularly in urban areas. ADUs offer a practical solution to this problem by allowing homeowners to create additional dwelling units on their properties. These units can serve as rental properties, housing for family members, or even be sold separately in some cases, as permitted by recent legislation. AB 434 facilitates this process, making it more feasible for homeowners to contribute to the housing supply.

Promoting Sustainable Development

ADUs are not just a housing solution but a sustainable one. They make efficient use of existing residential land and infrastructure, reducing the need for new developments that can strain resources and impact the environment. By promoting the construction of ADUs, AB 434 supports sustainable growth and helps communities maximize their existing spaces.

Never been a better time to build an ADU

AB 434 is a pivotal law that aims to simplify and expedite California’s ADU planning and construction process. With pre-approved ADU plans becoming available on city websites, homeowners will have access to various designs that can save time and money. The involvement of architects ensures that these plans are of high quality and compliant with regulations, although some property-specific adjustments may be necessary. By addressing the fees and efficiency of the approval process, AB 434 supports the broader goal of increasing housing options and addressing the housing crisis in California. For more detailed information, homeowners and property developers are encouraged to consult the official text of AB 434 and take advantage of this opportunity to enhance their living spaces.

Contact Acton ADU today to learn more about our pre-approved plans and Build Ready ADUs.

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