The Essential Guide to ADU Regulations in California: What You Need to Know | California ADU Regulations

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Looking to expand your living space? Maybe you need a separate spot for family when they visit, or you’re thinking about an extra rental unit for some additional income, or you just want a little more room to move around. If that’s the case, you might have already heard about Accessory Dwelling Units, or ADUs. They’re a smart and increasingly popular way to add more space to your property with style and function.

California ADU Regulations: Expert Guidance for Your Project

As interest in accessory dwelling units (ADUs) increases, a growing number of California homeowners are considering their construction. According to a 2016 McKinsey report, California could boost its housing supply by as many as 790,000 units if homeowners embraced the addition of ADUs to their properties.

However, with numerous California ADU rules and conditions to navigate, where should you start? In this comprehensive guide, we’ll explore everything from the basics of ADUs to navigating California’s specific regulations, ensuring you’re well-equipped to expand your living space or investment portfolio.

Let’s start by defining what an ADU is and the various forms it can take, laying the groundwork for understanding its potential on your property.

What Qualifies as an ADU?

Before exploring ADU regulations in detail, let’s first define what constitutes an ADU in California. According to the ADU Handbook created by the California Department of Housing and Community Development (HCD), ADUs are housing units intended to accommodate one or more individuals.

At Nestadu, we specialize in designing and building both site-built and prefab ADUs tailored to your property’s unique needs, ensuring a seamless integration from concept to completion.

ADU designs and structures can vary and include options such as:

1. Standalone ADU; A standalone unit separated from the primary dwelling

2. Attached ADU; A unit connected to the primary residence like a garage or basement

3. Conversion of Existing Space; Structures already present on the property, such as garages or storage areas, turned into independent living spaces

4. Junior Accessory Dwelling Unit (JADU); A type of conversion within the dwelling itself

Each ADU type has its own size, layout, and specific rules and regulations

It’s no secret that building ADUs in California has been increasing. Recent studies show that existing state laws have paved the way for 1.5 million housing units.

Following these regulatory changes, the number of ADU permits issued in 2019 saw a significant increase from the previous year. Although construction timelines and financing may cause delays in completions they have more than tripled during this time frame.

Navigating California’s ADU regulations can be a complex task. Nestadu’s team of experts is here to guide you through each step, from a feasibility assessment to ensure your project aligns with state laws to handling all local permitting processes.

With a clear picture of what ADUs can look like, we’ll now delve into the regulations governing their construction in California, helping you navigate the legal landscape with ease.

California ADU Regulations


Notable Changes in ADU Laws

Recent legislative changes have significantly impacted ADU development. Here’s how these updates could benefit your ADU project:

Expanding the Units                                                     

Understanding the recent expansion in allowable ADU units is crucial for maximizing your property’s potential. Let’s explore how these changes may affect homeowners

Before, homeowners could only have one ADU per property. However, with bills like AB 68, there are now opportunities for units;

  1. Single-family lots can now have one ADU (attached or detached) up to 1200 sq ft and one JADU up to 500 sq ft.
  2. Multi-family lots can accommodate attached ADUs and two detached ADUs.

This expansion in permissible units offers homeowners fresh opportunities to augment their property with extra housing options. By permitting ADUs on both family and multi-family lots, homeowners can make better use of their land and provide more housing choices for renters or family members.

Removing the Owner Occupancy Requirement

One of the pivotal changes in ADU regulation is the removal of the owner-occupancy requirement. Discover how this can open new opportunities for property investors and owners alike.

One major obstacle to building ADUs in the past was the requirement that either the main residence or the ADU itself must be occupied by the property owner. Recent legislation has removed this requirement, simplifying the process for homeowners to add ADUs.

Landlords and investors, in particular, benefit from this change, as it allows them to generate rental income from an ADU without needing to reside on the property.

The removal of the owner-occupancy requirement enables more homeowners to consider building ADUs as an investment opportunity.

Less Strict Requirements for Size and Lot

Before, strict guidelines governed the size of ADUs and the types of properties eligible for their construction. However, recent modifications in ADU regulations have eased these restrictions, making it simpler for homeowners to erect ADU requirements.

The state has removed limitations on minimum lot size, ADU lot coverage, and floor area ratio, enabling homeowners to construct ADUs on lots. Additionally, the minimum size requirement for ADUs has been reduced to 800 sq ft, allowing homeowners to construct smaller units that provide significant extra living space.

These relaxed criteria provide homeowners with flexibility in designing and constructing ADUs that cater to their needs and preferences. Whether seeking to add a rental unit, create a home office, or provide living space for family members, these regulatory adjustments make it more attainable for homeowners to meet their ADU-related objectives.

Reduction in Impact Fees

One of the obstacles to ADU development in the past was the cost of impact fees imposed by local governments to offset the effects of new construction on public infrastructure.

Recent changes in the law have made it easier for homeowners to add dwelling units (ADUs) on their properties by either reducing or eliminating impact fees.

ADUs up to 750 square feet are exempt from impact fees, whereas larger units incur fees proportional to their size. This decrease in costs associated with impact fees has made building ADUs more affordable and accessible for homeowners who were previously put off by the expenses.

Simplified Approval Process

One of the challenges homeowners faced when considering building ADUs was the time-consuming permitting process. However, recent legislation has simplified this process, enabling homeowners to obtain permits more quickly and easily.

Local authorities must now approve or reject ADU permit applications within 60 days of submission, thereby expediting the approval process.  This streamlined approval system minimizes delays and makes obtaining permits easier, allowing homeowners to advance with their ADU projects more smoothly.

Exemption from Parking Requirements

Parking regulations have historically posed a barrier to constructing ADUs in areas with limited parking spaces. New regulatory adjustments have exempted certain ADUs from parking requirements, making it easier for homeowners to build them.

Specific ADUs are now granted exceptions from parking mandates for those situated near transportation or within historically significant areas. Additionally, homeowners associations (HOAs) cannot obstruct the construction or use of ADUs, further reducing barriers to their development.

These exemptions enable homeowners to concentrate on constructing ADUs that align with their needs and preferences without the burden of parking obligations. Whether they opt for a backyard cottage or converting a garage into a unit these exemptions streamline the process for homeowners to capitalize on the advantages of ADUs.

Financial Assistance Opportunities

Financing an ADU can be a hurdle, but recent adjustments have introduced several financial assistance opportunities. Here’s how you can leverage these to your advantage:

Financing your ADU project is made easier with Nestadu, as we help you navigate through the various grants, loans, and incentives available for California homeowners, making your dream ADU a reality within your budget.

To encourage ADU development, state and local agencies provide grants, loans, and incentives, making it financially easier for homeowners to realize their ADU plans.

For example, CalHFA offers a $40,000 grant to help cover development costs for those building ADUs. These financial assistance programs can offset the costs of building an ADU, making it a viable option for budget-conscious homeowners.

Navigating the financial aspects of ADU construction can be complex. Nestadu simplifies this process by offering guidance on the most suitable financing options available for your project, ensuring you receive the best possible support without the need to look elsewhere.

Proposed Changes to the 60-Day Rule

Under Assembly Bill 2221, it is now required that all agencies responsible for reviewing ADU plans in California must provide a response within 60 days of plan submission. This streamlined process significantly reduces waiting times for approval, allowing you to move forward with your ADU project more swiftly and with greater predictability.

This adjustment targets an issue in the ADU permitting process, which has historically been marred by delays and bureaucratic hurdles. By setting a fixed timeframe for agency responses, homeowners can proceed with their ADU projects with speed and confidence.

Updates to ADU Height Regulations

AB 2221 has also revised height restrictions for ADUs, offering homeowners increased flexibility. The updated rules permit varying heights based on factors like proximity to transportation and existing structures on the property.

The flexibility in height regulations now allows for more creative design possibilities, enabling homeowners to tailor their ADU projects to their unique vision and property constraints Whether opting for a two story unit or a single story dwelling these adjusted height limitations simplify the process of creating living space.

Elimination of Unpermitted Conditions

Senate Bill 897 removes constraints associated with conforming zoning conditions, building code infractions, or unauthorized structures. This significant legislative shift opens up new opportunities for homeowners to enhance their properties, even those previously constrained by zoning or code violations, paving the way for a smoother ADU development process.

Previously homeowners might have been deterred from constructing ADUs due to concerns about zoning or building code violations on their property. However with these unauthorized conditions eliminated as impediments to ADU development homeowners can proceed with their projects with confidence and without worrying about legal consequences.

Senate Bill 9 (SB9)

One of the housing laws enacted in 2022 is Senate Bill 9 (SB9) which brings forth two provisions;

1. Dual unit construction; Homeowners can now erect two housing units on lots designated for one unit.

2. Urban Lot Division; Family residential lots can be divided into two parcels, allowing for up to four units on a traditionally single-unit lot.

SB9 represents a pivotal change in California’s housing landscape, encouraging denser development and offering homeowners new ways to contribute to addressing the housing shortage.

It is crucial to differentiate between SB9 units and ADUs as they are considered dwelling units to varying regulations.

What’s New in California’s ADU Laws 2024?

California ADU Regulations

Source: Pexels

Accessory Dwelling Units (ADUs) have been getting attention in California recently thanks to laws like AB 1033 AB 976 and AB 434. These laws aim to simplify California ADU regulations to make them more accessible and easier to build.

Lets dive into how these rules impact residents and property developers in California.

Introducing AB 1033

In October 2023, the passing of AB 1033 signaled a transformation in ADU regulations by permitting the sale of ADUs separated from primary residences on a property. This opens new possibilities for property owners, though it comes with certain limitations.

  • Local governments have the authority to enact ordinances allowing for the sale of ADUs, although it is not mandatory.
  • Selling an ADU separately entails converting the property into a recognized “condominium,” necessitating procedures and approvals.
  • Property owners with existing loans must seek approval from lenders before selling any portion of their loan-secured property.
  • It is essential to grasp the consequences of converting a property into a “condominium” as it could impact the value of the remaining residence.

Property owners are advised to seek guidance from legal and real estate experts when navigating the intricacies of selling ADUs under AB 1033.

The ability to sell ADUs separately could revolutionize the housing market in California, offering more flexibility for property owners and potential new pathways to homeownership.

New Legislation on ADUs – AB 976

AB 976 addresses concerns surrounding “owner occupancy” restrictions on ADUs that were permitted between January 1, 2020, and January 1, 2025.

  • This law eliminates government-set deadlines for owner occupancy restrictions, giving property owners greater flexibility in renting out their ADUs.
  • Local authorities can still control durations exceeding thirty days.
  • AB 976 guarantees that municipalities cannot enforce owner occupancy rules on ADUs beyond January 1, 2025.
  • Property owners now have increased freedom to lease out their ADUs without occupancy constraints.

Removing owner occupancy restrictions until at least 2025 offers ADU owners and potential investors an extended period of flexibility, potentially increasing the appeal of ADU development as a long-term investment strategy.

New ADU Legislation – AB 434

AB 434 stipulates that all cities and towns in California must establish approved ADU design schemes by January 1, 2025. The goal of this law is to simplify the planning and construction process for ADUs by offering approved designs that property owners can utilize.

  • Municipalities must accept submissions for approved ADU designs. Make them accessible on their official websites.
  • Although architects play a role, in securing design pre approvals users may be required to pay fees to use these designs.
  • Pre-approved designs may still need adjustments to fit the characteristics of each property.
  • Municipalities may apply fees for the review of approved designs, similar to standard planning review fees.

By mandating pre-approved ADU designs, this legislation aims to significantly reduce the barriers to entry for homeowners interested in ADU development, democratizing access to affordable housing solutions.

Restrictions prohibited by local ADU laws

Here are some other restrictions that are not allowed by California ADU laws in 2024;

  • Local governments cannot set rules about lot coverage or minimum lot size.
  • They cannot demand replacement parking if a garage, carport, or covered parking structure is removed to build an ADU or converted into one.
  • Homeowners associations (HOAs) cannot prevent or unreasonably limit the construction of ADUs on family properties.
  • Local agencies are not permitted to levy impact fees on ADUs smaller than 750 square feet.

These prohibitions on local restrictions are designed to streamline the ADU development process, ensuring that homeowners can maximize their property’s potential without undue burdens.

While statewide laws provide a framework for ADU development, the specific requirements can vary significantly from one town or municipality to another.

At Nestadu, our team boasts extensive expertise in understanding and navigating the diverse regulations across California. We are committed to ensuring that all local requirements are meticulously followed, guaranteeing a smooth and compliant ADU project from start to finish.

Now that you’re familiar with the regulations and financial aids, let’s walk through the steps to bring your ADU project to life, from concept to construction.

Steps to Construct an ADU in California

Like any construction project, there are steps you need to follow to turn your ADU idea into a reality in your backyard. Here’s an outline of the process;

Conduct research

Start by looking into the regulations and building codes in your area, including any requirements from the Homeowners Association (HOA). Make sure your property meets all the criteria for constructing an ADU.

Decide whether to go for a prefab ADU or a custom-built unit. Each choice comes with its pros and cons concerning cost and customization. Consider the features that are important based on how you plan to use the space.

Working with Professionals and Contractors

Choosing the right partner for your ADU project is crucial. At Nestadu, we provide transparent cost estimates and expert guidance tailored to your specific needs, ensuring a seamless and informed decision-making process. Consider factors like expenses, project timelines, and quality of work.

Ensure that the professionals and contractors you hire have been vetted, hold licenses, and carry insurance. Double-check their credentials if necessary. Ask for references if needed.

At Nestadu, we are backed by a team whose members have extensive experience in constructing high-quality single-family homes and ADUs. Our professionals are not only licensed and insured but also bring a rich heritage of craftsmanship and expertise to every project.

This depth of experience ensures that each ADU we design, build, and install meets the highest standards of quality and customer satisfaction. We invite you to partner with us, leveraging our team’s expertise for your ADU project, and experience the difference that professional knowledge and dedication can make.

Securing the Required Permits and Approvals

Once your plans are set and you’ve chosen a contractor, the next phase involves securing the necessary permits and approvals. Reach out to your city or county office for permitting. There are permits needed for any construction or additional ADU, such as building codes and utilities.

If you’re collaborating with an ADU manufacturer, they will take care of all the permitting tasks for you. This can streamline the process. Reduce stress since they are well-versed in regulations and procedures.

Start Construction

After obtaining the permits it’s time to begin construction. Custom built or stick built ADUs are put together on site which means there will be a construction zone on your property during this phase. The timeline for constructing ADUs can vary depending on construction challenges and design choices.

Prefabricated ADUs are built off-site in a controlled environment, which guarantees high-quality craftsmanship. Only site preparation and installation using cranes are required on-site, making the process faster and more predictable.

Inspections and Finalizing the ADU

Every ADU must undergo an inspection to confirm compliance with building codes and regulations.

Prefab ADUs are less likely to encounter issues during inspection as their designs have been pre-approved and thoroughly reviewed.

Once your ADU successfully passes inspection, it is ready for occupancy. Having a constructed ADU can provide living space, generate rental income, or cater to any other purpose you envision.

Managing an ADU project from start to finish requires extensive knowledge and experience. At Nestadu, we offer a comprehensive service that covers everything from design and permitting to construction and installation, allowing you to enjoy a stress-free project with expert oversight.

From the initial design phase to the final construction, Nestadu stands by your side. Whether you’re looking to build a custom site-built ADU or configure a prefab unit, our comprehensive service includes everything from design to installation using cranes for prefab units, ensuring a hassle-free process.

With these steps in mind, you’re well on your way to adding valuable space to your property. Let’s recap the key takeaways and consider your next moves.

Final Thoughts

ADUs provide California homeowners with opportunities to improve their properties, generate income, and meet housing needs. Keeping abreast of the latest regulations and leveraging available resources will ensure your project’s success.

While the journey to adding an ADU to your property may seem complex, partnering with Nestadu ensures you have an experienced ally every step of the way. We’re dedicated to transforming your property with an ADU that perfectly meets your needs, handling all aspects, from feasibility assessments to construction and installation. Let’s make your ADU project a seamless and successful endeavour.

Ready to transform your property with an ADU? Contact us for expert guidance and take the first step towards expanding your living space today.

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