In California, Accessory Dwelling Units (ADUs), also known as granny flats, in-law units, or secondary units, have gained significant attention as a means to address housing shortages, provide affordable housing options, and offer additional income streams for homeowners. The regulations governing ADU construction have undergone several changes in recent years to encourage their development and streamline the process. However, whether you can build an ADU before the main house largely depends on local zoning regulations, building codes, and other factors.

Historically, many municipalities in California required that the primary residence be constructed before an ADU could be built on the same property. This requirement was in place to ensure that ADUs were truly secondary units and not intended to circumvent zoning laws or land use regulations. However, in response to the housing crisis, the state and local governments have implemented various policies to promote ADU construction, including relaxing some of these requirements.

More recently, in California, you can build an ADU before the main house, subject to certain regulations. Recent changes in legislation, including AB 881 and SB9, have relaxed certain zoning restrictions, so there is more flexibility for property owners and developers. However, there are various considerations that impact practicality, including:

  • Size and setback regulations
  • Utility connections
  • Access
  • Construction logistics

There would have to be a detailed plan for both properties ahead of time, and this would need to be approved by the local government. As such, consultation with local authorities and a thorough understanding of the evolving ADU laws are absolutely essential.

Your ability to build an ADU before the main residence in California will be influenced by zoning restrictions, particularly relating to land use policies in different cities. Local ordinances dictate rules about things like:

  • Setbacks
  • Size limitations
  • Zoning classifications

These can vary across municipalities. Recent legislative updates, like AB 881, have introduced easing to zoning restrictions, but it is still crucial to adhere to local regulations.

When creating your project design, you will need to think about zoning classifications, setback requirements, and local land use policies. Consult local planning departments and keep abreast of zoning updates. If you remain compliant when planning your project, you should be able to get the necessary permits and navigate the intricate ADU construction laws in California successfully.

With an increased demand for ADUs on land, there are likely to be more instances of people planning to build them on properties where the main dwelling hasn’t yet been constructed, so the need to build an ADU before the main house could increase in California.  The regulations will inevitably vary between different regions, so it is important to be fully informed of where you stand in your locale.

In areas where ADU construction is actively encouraged, local governments may have adopted policies that permit ADUs to be built concurrently with or even before the main house. These policies are typically aimed at increasing housing stock quickly and efficiently. However, it’s essential to verify this with the local planning department or building authority, as regulations can vary significantly from one jurisdiction to another.

Furthermore, even if local regulations technically allow for ADUs to be built before the main house, practical considerations such as access to utilities, infrastructure requirements, and other logistical factors may still need to be addressed. Additionally, financing and permitting processes may differ depending on the construction sequence.

In order to secure permits to build an ADU before the main house in California, you will have to create a detailed plan for both constructions that adheres to all the local zoning and other building regulations. To achieve this, you will need to do the following:

  • Familiarize yourself with local regulations.
  • Consult with local planning departments and other professionals.
  • Create and submit preliminary plans with the help of local experts.
  • Attend public hearings (if required).
  • Obtain the approvals from local planning departments and secure building permits.
  • Oversee construction.

The absence of the primary residence will mean that adherence to building codes and standards will be scrutinized during construction of your ADU. As such, you will need to be familiar with:

  • The California Residential Code (CRC)
  • Local building codes
  • Zoning ordinances
  • Fire safety standards
  • Energy efficiency standards
  • Plumbing/electrical codes
  • Accessibility requirements
  • Structural engineering standards
  • Permitting and inspections
  • Health and safety

If you are able to keep on top of all these requirements, you may complete your project and have a very desirable property.

While recent legislative changes in California have made it easier to build ADUs and have relaxed many restrictions, whether you can build an ADU before the main house depends on local regulations. It’s crucial to research and understand the specific zoning ordinances and building codes in your area and consult with relevant authorities to ensure compliance with all requirements.