How to Legalize Unpermitted ADU & Garage Conversions

Jul 28, 2023 | ADU

In response to the housing crisis, many state and local governments have taken initiatives to promote the development of Accessory Dwelling Units (ADUs). These secondary housing units, also known as granny flats or in-law units, can offer affordable housing options and additional income streams for homeowners.

Unpermitted garage conversions have become a dominant sight in Los Angeles and its neighboring areas, with such additions seemingly present on every block. However, with the legalization of accessory dwelling units (ADUs), local authorities are now taking strict measures to address unpermitted constructions, particularly focusing on illegal garage conversions.

As an owner facing the consequences of unpermitted construction, you are left with two primary options to resolve the situation:

  1. Restore the Building to its Previous Condition: The first option involves reverting the unpermitted construction back to its original state. This means dismantling the unauthorized additions and restoring the garage to its original use and appearance. This route may be preferred by some homeowners who wish to avoid legal complexities and want to comply with local regulations promptly.
  2. Go Through the Process of Legalizing the Unpermitted Work: The second option entails embarking on the journey of legalizing the unpermitted construction. This process involves obtaining the necessary permits and approvals from the relevant authorities to bring the garage conversion up to code and officially recognize it as a legal accessory dwelling unit (ADU). While this option may require more effort, time, and financial investment, it can be a worthwhile endeavor, as it grants the homeowner the benefits and legitimacy of having a legal ADU on their property.

Considering the crackdown on unpermitted additions, carefully considering these two options, and understanding the local regulations can help homeowners make informed decisions regarding their unpermitted garage conversions.

This article explores the reasons for legalizing ADUs, the steps involved in the process, and the various benefits and drawbacks associated with this endeavor.

What is Illegal ADU?

Before delving into the process of legalizing unpermitted ADUs, it’s crucial to understand what makes an ADU illegal or unpermitted. In general, homeowners must obtain the necessary permits and certificates of occupancy from their local jurisdiction to legalize an ADU fully. Failure to complete the permitting process results in the ADU being deemed illegal.

Unfortunately, some homeowners may bypass the permit process to save time and money. However, this decision can lead to severe consequences down the line, including endangering the occupants of the ADU and incurring hefty fines and legal actions.

The Path to ADU Legalization

To combat the housing crisis and make ADUs a viable option for affordable housing, many states, including California, have implemented ADU development programs. As a part of these programs, local governments have introduced unit legalization initiatives to encourage homeowners to bring their unpermitted ADUs up to code.

For instance, Los Angeles City Planning has introduced the Unpermitted Dwelling Unit (UDU) Ordinance, enabling property owners to legalize their ADUs by meeting specific life safety conditions. Following a stipulated six-step process involving coordination with City Planning, the Department of Building and Safety (LADBS), and the Housing and Community Investment Department (HCIDLA), these newly legalized units can enter the housing market.

Pros & Cons of Legalizing ADUs

People who built ADUs without permits often did so because they believed the drawbacks of obtaining permits outweighed the benefits. However, with the introduction of new laws encouraging ADU development, legalizing unpermitted ADUs has become increasingly advantageous.

Benefits of Legalizing ADUs

The primary benefit of legalizing ADUs is mitigating the high-risk consequences associated with owning and renting out illegal units. Renting an unpermitted ADU can lead to severe penalties and legal actions against the homeowner, including potential refunds for rent and utilities to tenants. Legalizing the ADU ensures continuity of rental income and safeguards both the homeowner and the tenants.

Moreover, in case of accidents such as earthquakes, fires, or floods, insurance companies typically do not cover damages for unpermitted ADUs. By legalizing the unit, homeowners and tenants can benefit from proper insurance coverage, ensuring financial security in times of crisis.

Another compelling advantage of legalizing an ADU is its potential to add value to the homeowner’s property. When selling the property, a legalized ADU enhances its appeal and market value, making it a more attractive investment compared to a property with an illegal and risky ADU.

Drawbacks of Legalizing ADUs

The main drawback of legalizing an unpermitted ADU is the associated cost. Depending on the extent of non-compliance with building codes, bringing the unit up to living standards can be quite expensive and time-consuming. However, if the ADU was built with some consideration for setback regulations and building codes, the legalization process becomes more manageable and less costly.

Considering the benefits outweigh the drawbacks, legalizing your ADU is a wise decision. Doing so not only eliminates the risk of financial losses through fines and legal actions but also increases your property value. Even if the ADU serves purposes other than rental income, such as house hacking to pay off the primary mortgage, legalizing it can ensure insurance coverage and future rental opportunities.

Step-by-Step Guide to Legalizing Unpermitted ADUs

Step-by-Step Guide to Legalizing Unpermitted ADUs

1: Initial Assessment and Feasibility Study of the Unpermitted ADU

Assess the Existing ADU Unit The first step towards ADU legalization is to assess the current unit. Since unpermitted ADUs may not comply with city code guidelines, it is essential to understand the ADU zoning laws of your local government. This assessment should cover aspects such as energy restrictions, the presence of a kitchen and bathroom, parking requirements, plumbing, electrical systems, setback requirements, square footage requirements, and structural standards.

In some cases, you might want to start with an ADU feasibility study. This study is essential as it allows both you and your design team to assess whether developing an ADU on your property is viable. Through this study, you can gain valuable insights into size limitations, guidelines, and potential challenges related to your ADU project. Here are the steps to follow for an effective feasibility study:

  1. Create a Site Map: Begin by generating a site map that accurately represents the dimensions of your property and its existing structures. This visual depiction will be the foundation for incorporating relevant information during the feasibility study. You can manually create the site map or utilize online services like Draw Site Plan (use coupon code LEVIDSP for a 5% discount).
  2. Schedule a Meeting with the Local Planning Department: Arrange a meeting with your local planning department to gather additional information and insights. During this meeting, seek details about setback requirements, height limitations, maximum allowed ADU size, parking regulations, existing easements, and any other relevant rules. Moreover, inquire about the need to navigate through review boards or committees (e.g., HOA, Historical, Coastal, etc.) for necessary approvals. Determine if additional surveys, engineering work, or calculations beyond the basic requirements are necessary.
  3. Incorporate Information on the Site Map: After gathering the necessary data from the local planning department, incorporate it onto your site map. Clearly mark setback requirements, height limitations, parking regulations, and any other relevant guidelines or restrictions. This visual representation will help you better comprehend the implications of these regulations on your ADU project and serve as a reference point for informed decision-making.
  4. Use online ADU resources: If you have already hired an ADU design team, they will typically handle the feasibility study for you. However, in the absence of a design team, you can explore online resources like, which provides information on ADU guidelines for various counties and cities in California. Additionally, you can refer to the feasibility report sample included in your document packages for an idea of what a comprehensive feasibility study entails.

Conducting a thorough feasibility study will provide you with a clear understanding of the possibilities and limitations associated with developing an ADU on your property. This knowledge will guide your design and planning process, ensuring that your ADU project complies with local regulations and fulfills your specific requirements.

2: Designing and Planning for Necessary Changes

Create Plans for Changes Once you identify the required changes, If you possess skills in operating design and planning software, you can embark on creating your own floor plans and possibly even 3D renderings. If you lack this software knowledge, you can start by making hand drawings of floor plans and elevations as a first step. Alternatively, there are websites where you can purchase pre-made ADU designs and architectural drawings.

If you opt to hire a design and planning team, you should identify the specific professionals you will need, a task best accomplished during the Feasibility phase.

You have the option to hire individual professionals for each requirement or choose a design firm that offers multiple services under one roof.

In certain cases, these professionals may not need to be licensed, but there are instances where licensure is mandatory. It’s important to check with your local planning department to ascertain their requirements. Opting for non-licensed services can potentially save you money, but it’s crucial to ensure that these service providers are reputable and experienced in handling projects similar to yours.

The basic requirements typically involve architectural, structural, and T24 (Energy Calculations). For some ADU sizes, a stormwater system may also be considered a basic requirement.

For specific cases, MEP Engineering, Land Survey, and Soil Engineering services may be necessary. If you require any of these services, it is imperative to engage licensed professionals for the job.

3: Securing City Approval for the Updated ADU Plan

Submit ADU plans for Approval Submit the detailed plans to the city for approval.

The process of plan check, obtaining clearances, and securing approval for a construction permit is carried out in collaboration with your local building department and its various offices.

If you have engaged a design firm to assist with your ADU plans, inquire about the cost of having them handle the plan check and permit process. This procedure can be time-consuming and involves navigating through different offices. Alternatively, if you choose to handle it yourself, contact your local planning and building department to gain a clear understanding of the tasks involved. Request a handout outlining the process, as it can help you navigate through the requirements.

It’s crucial to maintain records of all submitted documents, communication with city representatives, and payments made throughout the process. These records will prove useful when addressing any questions that may arise.

Once the construction drawings are completed, you can submit them to the city’s planning and building and safety departments to initiate the plan check process. For historical properties, there will be a review by the historical preservation review board, and coastal-zoned properties will undergo review by the coastal committee. Additionally, properties under special architectural review boards will need to undergo those reviews before the submission for plan check with the city.

After the plan check is completed, you will receive the plans back to address any corrections and obtain clearances from various departments, including utility departments such as power, water, gas, sanitation, grading, transportation, and fire department etc… Each department will sign and approve the project, and if there are any specific requirements for utility connections, they will provide guidance.

Once corrections and clearances are completed, a second submittal of the plans and associated documents will occur, followed by a final plan check review. During this review, the assigned city plan checker will confirm that all requirements have been met. If everything is in order, the plans will be stamped as approved, and you will be ready to receive your construction permit.

4: Launching Construction and Staying on Track with Inspections

Start construction and inspections with approved plans and necessary permits in hand, hiring a reputable contractor with experience in ADU construction and knowledge of local laws will help avoid common mistakes and streamline the construction process.

Throughout the construction process, it is essential to maintain detailed records and accounts to ensure that the agreed-upon contract with your contractor is being followed. Here are some steps to help you keep track:

  1. Keep a copy of the permit and inspection card.
  2. Maintain physical copies of the contract and all change orders that occur during the project.
  3. Document any verbal correspondence with your contractor, noting dates and times. Keep records of meeting minutes, preferably on a weekly basis.
  4. Take pictures of the work completed, categorize them by trade, and include the dates they were taken.
  5. Hold onto physical copies of all warranties provided.
  6. Organize a folder with physical copies of payment receipts, ensuring that payments are made based on progress in line with the schedule of values. The final payment should account for at least 10% of the contract amount.
  7. For each payment, request a signed lien release from the contractor.
  8. As your project nears completion, create a checklist to ensure that all aspects of the work have been completed according to the contract’s standards.
  9. Request to be present during periodic inspections conducted by city officials, as their feedback can help you ensure that the work is on track and meeting regulations.
  10. Upon project completion and when making the final payment, obtain a signed lien release from the contractor.

By diligently keeping records and adhering to these practices, you can effectively monitor the construction and inspection progress and ensure that the work is carried out as per the agreed-upon contract terms and approved plans.

Cost of Legalizing Unpermitted ADUs

The cost of legalizing an unpermitted ADU varies widely based on the extent of required changes to bring the unit up to code. Costs can range from a few thousand dollars to over a hundred thousand dollars, depending on the complexity of the project.

Financing Options for ADU Legalization Fortunately, several financing options are available for ADU legalization. Homeowners can explore grants and incentives offered by states and local jurisdictions. Additionally, renovation loans, cash-out refinance, and home equity lines of credit (HELOC) can provide viable funding solutions.

In conclusion, legalizing your ADU offers numerous advantages, including additional rental income, increased property value, and compliance with insurance requirements. By following the step-by-step guide and seeking expert assistance, homeowners can successfully legalize their unpermitted ADUs and contribute positively to their communities by providing affordable housing options.


  • What is an Accessory Dwelling Unit (ADU)?
    An Accessory Dwelling Unit (ADU), also known as a granny flat or in-law unit, is a secondary housing unit that can be added to a property. They offer affordable housing options and additional income streams for homeowners.
  • What makes an ADU illegal or unpermitted?
    An ADU is deemed illegal or unpermitted when homeowners fail to obtain the necessary permits and certificates of occupancy from their local jurisdiction to legalize the unit. Bypassing the permit process may lead to severe consequences, including endangering occupants, and incurring hefty fines and legal actions.
  • What are the benefits of legalizing ADUs?
    Legalizing ADUs mitigates the high-risk consequences associated with owning and renting out illegal units. It ensures continuity of rental income, safeguards both the homeowner and the tenants, and offers insurance coverage in case of accidents. Moreover, a legalized ADU can add value to the homeowner’s property, making it more appealing in the real estate market.
  • What are the drawbacks of legalizing ADUs?
    The primary drawback of legalizing an unpermitted ADU is the associated cost, as bringing the unit up to living standards can be expensive and time-consuming. However, if the ADU was built considering setback regulations and building codes, the legalization process becomes more manageable and less costly.
  • What steps are involved in legalizing unpermitted ADUs?
    The steps to legalize unpermitted ADUs involve an initial assessment and feasibility study of the existing unit, designing and planning for necessary changes, securing city approval for the updated ADU plan, and then launching construction and staying on track with inspections. It’s a complex process that may require working with multiple professionals and agencies.
  • How much does it cost to legalize unpermitted ADUs?
    The cost of legalizing an unpermitted ADU varies widely based on the extent of changes required to bring the unit up to code. Costs can range from a few thousand dollars to over a hundred thousand dollars, depending on the complexity of the project.
  • What financing options are available for ADU legalization?
    Several financing options are available for ADU legalization, including grants and incentives offered by states and local jurisdictions. Additionally, homeowners can explore renovation loans, cash-out refinance, and home equity lines of credit (HELOC) as viable funding solutions.