Accessory Dwelling Units (ADUs) in Orange County: What You Need to Know

12/21/20233 min read


Are you considering adding an Accessory Dwelling Unit (ADU) to your property in Orange County, California? ADUs are becoming increasingly popular as homeowners look for ways to maximize their living space and increase the value of their properties. In this article, we will explore what ADUs are, why you should consider building one, and the regulations surrounding ADUs in Orange County.

What is an Accessory Dwelling Unit?

An Accessory Dwelling Unit, or ADU, is a separate living unit that is either attached or detached from the main home. It provides complete independent living facilities and can be located on the same lot or within the same structure as the main home. ADUs are commonly known as "mother-in-law apartments" or "granny flats" and are designed to accommodate additional occupants while maintaining privacy and independence.

Why Build an ADU?

There are several reasons why you might want to consider building an ADU on your property:

1. Additional Living Space

One of the main reasons homeowners choose to build ADUs is to create additional living space. ADUs provide a separate and self-contained unit that can be used for various purposes, such as housing elderly parents, accommodating adult children, or renting out for additional income.

2. Increased Property Value

Adding an ADU to your property can significantly increase its value. With the high demand for housing in Orange County, having an ADU can make your property more attractive to potential buyers or renters. It is a smart investment that can provide a substantial return in the long run.

3. Flexibility and Versatility

ADUs offer flexibility and versatility in terms of usage. You can use them as a home office, a studio, a guest house, or even as a rental property. The choice is yours, and you have the freedom to adapt the space to your specific needs.

4. Aging in Place

For homeowners who plan to age in place, ADUs provide a practical solution. They offer a separate living space that allows older adults to maintain their independence while staying close to their family and support network.

Regulations for ADUs in Orange County

Before you start building an ADU, it is essential to familiarize yourself with the regulations set by the Orange County Public Works Department. Here are some key points to consider:

1. Zoning Requirements

ADUs in Orange County must comply with specific zoning requirements. The property must be zoned for residential use, and the lot size must meet the minimum requirements set by the county. It is crucial to check the zoning regulations for your specific area before proceeding with your ADU project.

2. Size and Design Restrictions

There are limitations on the size and design of ADUs in Orange County. The maximum size allowed for an ADU is typically determined by the size of the main home or the lot. Additionally, the design of the ADU must be in harmony with the existing architecture and neighborhood aesthetics.

3. Parking Requirements

Orange County requires ADUs to provide parking spaces for the additional occupants. The number of required parking spaces depends on the size of the ADU and the existing parking availability on the property.

4. Building Permits

Before starting construction on your ADU, you must obtain the necessary building permits from the Orange County Public Works Department. These permits ensure that your ADU meets the safety and building code requirements.


Adding an Accessory Dwelling Unit to your property in Orange County can provide numerous benefits, including additional living space, increased property value, and flexibility in usage. However, it is crucial to familiarize yourself with the regulations and requirements set by the Orange County Public Works Department before starting your ADU project. By following the guidelines and obtaining the necessary permits, you can create a functional and valuable living space that enhances your property and meets your specific needs.




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