ADU Permit Cost Orange County

ADU Permit Cost Orange County

ADU Permit Cost Orange County: What You Need to Know

Adding an Accessory Dwelling Unit (ADU) to your property in Orange County, CA can be an excellent way to maximize the use of your land and potentially generate rental income. However, before you embark on this journey, it’s crucial to understand the various costs associated with obtaining the necessary permits. These costs can vary depending on factors like the city you’re in and the size of the ADU you plan to build.

Permit Fees

One of the significant expenses you’ll encounter when building an ADU in Orange County is permit fees. These fees cover the cost of reviewing your plans and ensuring that your ADU complies with local building codes. The exact permit fees can vary significantly between cities within Orange County, but they generally range from $3,000 to $7,000.

The variation in permit fees is primarily due to the differences in city regulations and requirements. Some cities have more streamlined processes, while others may have stricter guidelines, which can lead to higher fees. Additionally, the size and complexity of your ADU project can also impact the permit fees.

It’s essential to check with your local city government or planning department to get an estimate of the permit fees for your ADU; however, most cities will not give you an exact cost until plans are approved. They can provide you with detailed information on the application process, required documents, and approximate costs.

School Fees

In Orange County, there are additional fees associated with ADU construction, known as school fees. These fees are charged for ADUs over a certain size, typically 500 square feet or larger. School fees are meant to help support local schools by contributing to the cost of educating potential new residents in the ADU.

The exact amount of school fees can vary by city and school district but can range from a few thousand dollars to several thousand dollars. Keep in mind that these fees are typically a one-time expense paid during the permitting process.

It’s essential to consult with your local school district or city planning department to determine the specific school fees applicable to your ADU project. Understanding these fees in advance will help you budget accordingly.

Impact Fees

In addition to school fees, some cities in Orange County may impose impact fees on ADUs that exceed a certain size, typically 750 square feet or larger. Impact fees are intended to address the potential strain on city infrastructure and services caused by larger ADUs.

Like permit fees and school fees, the amount of impact fees can vary significantly depending on your location and the size of your ADU. These fees can range from a few thousand dollars to more substantial amounts.

To find out if your ADU project is subject to impact fees and to get an accurate estimate of the costs, you should contact your local city planning department. They can provide you with information on the specific impact fee requirements for your area.


Building an ADU in Orange County can be a rewarding investment, but it’s essential to be aware of the associated permit costs, school fees, and potential impact fees. Depending on your city and the size of your ADU, you could be looking at permit fees ranging from $3,000 to $7,000, school fees for ADUs over 500 square feet, and impact fees for ADUs over 750 square feet.

To ensure a smooth and cost-effective ADU construction process, it’s crucial to do your research, consult with your local planning department, and budget accordingly. By understanding the permitting costs and fees upfront, you can better plan your ADU project and make informed financial decisions. While the costs may seem daunting at first, the potential benefits of having an ADU, such as rental income or additional living space, can make it a worthwhile investment in the long run.

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