Costa Mesa ADU Guide: Everything You Need to Know

The city of Costa Mesa is one of the most desirable places to live in Orange County, California. But with rising home prices and limited space, many homeowners are looking for ways to maximize their property value. One solution gaining popularity is the addition of Accessory Dwelling Units – or ADUs – to their existing homes.

If you’re considering building an ADU in Costa Mesa, you’ll want to become familiar with the city’s zoning map, city planning process, specific plans, and local laws – including requirements for ADU construction and fence regulations.

But before we dive into those details, you’re probably wondering: is Costa Mesa an expensive place to live? And how much does it cost to build an ADU in Orange County?

This comprehensive Costa Mesa ADU guide will answer these questions and more, providing you with all the necessary information to make the most of your property and increase your home’s value with an ADU. So, let’s get started!

Costa Mesa Zoning Map

One of the key factors to consider when looking to build an ADU in Costa Mesa is understanding the city’s zoning map. This map is a crucial tool that outlines the different zones within the city and what type of structures are allowed to be built in each zone.

Understanding the Zones

Costa Mesa has several different zoning designations, including residential, commercial, and mixed-use. Each zone has different regulations and guidelines that dictate what type of development can occur within that zone.

Here are some of the most commonly found zones in Costa Mesa:

Residential Zones

  • R-1: Single-family residential zone
  • R-2: Multiple-family residential zone
  • R-3: High-density residential zone

Commercial Zones

  • C-M: Commercial manufacturing zone
  • C-1: Neighborhood commercial zone
  • C-2: General commercial zone

Mixed-Use Zones

  • MU-H: Mixed-use high-density zone
  • MU-V: Mixed-use vertical zone
  • MU-T: Mixed-use transitional zone

What You Need to Know

When planning to build an ADU on your property, it’s essential to understand the zoning regulations that apply to your property. Here are some key takeaways:

  • You must comply with the zoning designation assigned to your property.
  • Not all zones allow for ADUs to be built. For example, in the R-1 zone, ADUs are not allowed.
  • ADUs must adhere to the regulations within the zone they are built-in.
  • The city of Costa Mesa offers an online zoning map that you can use to determine your property’s zoning designation.

Understanding the Costa Mesa zoning map is critical when planning to build an ADU on your property. Ensure you comply with the zoning designation assigned to your property and that your ADU adheres to the regulations set within your zone. With a little research and careful planning, you can have your dream ADU built in no time.

Costa Mesa City Planning

Costa Mesa city planning is an essential aspect of building and managing a prosperous community. The city planners have several roles to play, and they must have a deep understanding of zoning laws, building regulations, and other crucial aspects of city planning. Here are some key takeaways about Costa Mesa city planning that you should know:

The Planning Department in Costa Mesa

The Costa Mesa Planning Department works to regulate land use, new construction, and development plans within the city. This department manages the processing and approval of permits for development projects and ensures all building and construction projects adhere to city ordinances and safety regulations.

Zoning Ordinances

Costa Mesa has zoning ordinances that control development, land use, and construction projects within the city’s boundaries. This is to ensure the city’s development is well-organized and meets the needs of the community effectively. Zoning ordinances ensure that each property is designated with a specific use, whether it is residential, commercial, or industrial.

Costa Mesa’s General Plan

The city of Costa Mesa’s general plan serves as a comprehensive guide for the future development of the city. It outlines the community’s vision for development, protecting the environment, transportation, safety, and other critical aspects of city life to meet the needs of the residents. The plan serves as a tool to guide city decision-makers, property owners, and developers to meet long-term goals.

Development Process

The development process involves several steps that require permits, approvals, and compliance with city regulations. Among the critical steps include site planning, environmental reviews, and construction planning, which require adherence to zoning laws, building codes, and other regulatory requirements.

Public Involvement

Costa Mesa’s city planning process involves public participation to ensure the community’s needs and interests are incorporated. Public involvement includes hearings, community meetings, and other participatory forums where residents can voice their opinions and concerns to guide city planning decisions.

In conclusion, planning is essential in any community’s development, and Costa Mesa’s city planning serves to help ensure a safe, prosperous, and healthy environment for all residents. Understanding these crucial aspects of city planning can help the community participate in the decision-making process as well as understand the outcomes of such decisions.

Costa Mesa Specific Plans

Costa Mesa has specific plans that govern land use and development within different areas of the city. These plans tailor the development standards for these areas based on their unique characteristics and needs. Here are some of the key points to keep in mind about Costa Mesa specific plans:

What are Costa Mesa specific plans?

Costa Mesa’s specific plans outline the development standards that apply to different areas of the city. For example, the Harbor Boulevard Specific Plan governs development along Harbor Boulevard, while the Mesa Verde Drive Specific Plan outlines the standards for Mesa Verde Drive. Each specific plan is tailored to the unique characteristics of the area it covers, such as the existing land use patterns, transportation infrastructure, and community needs.

Why are specific plans important?

Specific plans help ensure that new development fits in with the character of the surrounding area and meets the needs of the community. By tailoring the development standards to each specific area, the plans can help reduce conflicts between new development and existing uses. Specific plans also provide predictability for developers and property owners, as they know what to expect in terms of development standards when planning new projects.

What do specific plans cover?

Specific plans typically cover a range of development standards, such as building height, setbacks, parking requirements, and landscaping. They may also include regulations around the types of uses that are allowed in the area, such as commercial or residential, and any design standards that must be followed for new buildings.

How are specific plans created?

Specific plans are typically developed through a public process that involves input from community members, businesses, and other stakeholders. The city may also hire consultants to help develop the plan and conduct environmental reviews. The plan then goes through a review and approval process by the city council.

What are some of the specific plans in Costa Mesa?

Costa Mesa has several specific plans, including:

  • The Harbor Boulevard Specific Plan, which governs development along Harbor Boulevard between Adams Avenue and 19th Street.
  • The SoBECA (South Bristol Entertainment and Culture Area) Specific Plan, which covers the area surrounding South Bristol Street and Baker Street.
  • The Westside Specific Plan, which outlines development standards for the Westside area of Costa Mesa.
  • The Mesa Verde Drive Specific Plan, which governs development along Mesa Verde Drive.

Key takeaways

  • Costa Mesa’s specific plans tailor development standards to the unique characteristics of each area of the city.
  • Specific plans help ensure that new development fits in with the character of the surrounding area and meets the needs of the community.
  • Specific plans cover a range of development standards, such as building height, setbacks, parking requirements, and landscaping.
  • Specific plans are created through a public process that involves input from community members, businesses, and other stakeholders.
  • Costa Mesa has several specific plans that govern development in different areas of the city.

Costa Mesa ADU Requirements

Looking to build an Accessory Dwelling Unit (ADU) in Costa Mesa, California? There are certain requirements that you need to abide by to ensure your project meets the necessary criteria. In this section, we’ll break down the specific requirements you need to consider before starting your ADU construction project in Costa Mesa.

Size and Placement

  • The maximum size of your ADU cannot exceed 50% of the existing dwelling or up to 1,200 square feet (whichever is less).
  • ADUs must be situated to the rear or side of the existing main house and must comply with all setback requirements.
  • The maximum height of the ADU shall be no more than two stories or 25 feet, whichever is less.
  • The ADU must have a separate entrance from the main house.


  • If your ADU has one bedroom or less, you don’t need to provide any additional parking space.
  • If your ADU has two bedrooms or more, you’ll need to provide one additional parking space on your property.

Utility Connections

  • The ADU must be connected to the existing home’s utilities (water, gas, and electric).
  • The ADU must have independent and separate connections to the public sewer system.

Building Codes and Inspections

  • All ADUs must comply with the California Building Code, California Plumbing Code, and other relevant codes and standards.
  • You’ll need to obtain a building permit and pass all required inspections to ensure your ADU meets all safety codes.

If you’re planning on building an ADU in Costa Mesa, it’s essential to be aware of all the requirements. By adhering to these guidelines, you can ensure your ADU construction project is permitted and legal. However, it’s always best to consult with a professional builder or permit expeditor to ensure your project meets all legal requirements and codes.

Costa Mesa Fence Regulations

If you’re considering constructing a fence in Costa Mesa, California, there are some regulations that you should be aware of to avoid running into legal issues. Here are some key points to keep in mind:


  • A building permit is required for all fences over three feet in height.
  • Fences less than three feet high don’t require a permit unless they’re next to a public right-of-way (such as a sidewalk), in which case a permit is required to ensure that the fence doesn’t obstruct visibility or access.
  • The permit fee varies depending on the type and length of the fence, but it usually ranges between $150 and $300.

Height Restrictions

  • The maximum height for a fence within the front yard setback (the area between the street and the front of the building) is three feet.
  • Fences in the side and rear yards can be up to six feet high, but there are additional restrictions depending on the location of the fence relative to the property line and adjacent buildings.
  • If you live in a historic district, your fence may need to comply with additional regulations to maintain the character of the area.

Design Restrictions

  • Chain-link fences are not allowed in the front yard setback, but they are allowed in the side and rear yards.
  • Fences must be visually appealing and made of materials such as wood, masonry, or wrought iron. Vinyl fences are allowed in some circumstances as long as they can be made to look like wood or other approved materials.
  • Barbed wire and electrified fences are not allowed in residential areas.

As you can see, the fence regulations in Costa Mesa are quite comprehensive, but they’re designed to ensure that the city remains safe, visually appealing, and consistent with its rich history. By following these guidelines, you’ll be able to construct a fence that not only meets your needs but also complies with the local laws.

Costa Mesa Building Department

If you’re planning to build an ADU in Costa Mesa, you will need to deal with the Costa Mesa Building Department. This department is responsible for enforcing building codes, issuing permits, and conducting inspections to ensure that buildings are safe for occupancy. Here are some things you need to know:

The Permit Process

Before you start building your ADU, you will need to obtain a permit from the building department. The permit process involves several steps, including:

  • Submitting your building plans and other necessary documents
  • Paying the necessary fees
  • Waiting for the building department to review and approve your plans
  • Scheduling inspections throughout the building process

The building department has specific requirements for ADUs, such as minimum square footage, ceiling height, and outdoor living space. Be sure to review these requirements before starting your project to avoid costly mistakes.


Throughout the building process, the building department will conduct inspections to ensure that your ADU is complying with local building codes. You’ll need to schedule inspections at various stages of construction, such as foundation, framing, electrical, and plumbing. Failing an inspection will result in delays and additional costs, so be sure to communicate with the building department and address any issues promptly.

Working with the Building Department

Dealing with the building department can be daunting, but it doesn’t have to be. Here are some tips to make the process smoother:

  • Be patient: The permit process can take some time, so don’t expect to get your permit overnight.
  • Ask questions: If you’re not sure about something, ask the building department. They’re there to help you navigate the process.
  • Be organized: Keep all your documents in order and follow the building department’s instructions carefully.
  • Hire a professional: Consider hiring a contractor who has experience working with the Costa Mesa building department. They can help you avoid common pitfalls and ensure that your project is compliant with local codes.

In conclusion, building an ADU in Costa Mesa requires working with the building department to obtain permits and ensure compliance with local building codes. By being patient, organized, and working with experienced professionals, you can successfully navigate this process and build the ADU of your dreams.

Costa Mesa: Is It Expensive to Live In?

If you’re thinking about moving to Costa Mesa, one of the first things you might be wondering is whether it’s an expensive place to live. While there’s no straightforward answer to that question, there are a few things you can keep in mind as you consider your options.

Cost of Living

One of the biggest factors that will influence your overall living expenses in Costa Mesa is simply the cost of living. According to Best Places, the overall cost of living in Costa Mesa is about 54% higher than the national average. Here are a few areas where you can expect to feel the pinch:

  • Housing: The cost of housing in Costa Mesa is a major contributor to the overall higher cost of living. In fact, City-Data reports that the median home price in Costa Mesa is about $830,000, which is more than twice the national median. Rent can also be pricey, with a one-bedroom apartment averaging around $1,800 per month.
  • Food: The cost of food in Costa Mesa is about 17% higher than the national average, according to Best Places. This includes groceries as well as dining out. While there are certainly affordable options available, you may need to budget a bit more for food expenses.
  • Transportation: Another area where you might see higher costs in Costa Mesa is transportation. Depending on where you live and work, you may need to pay for public transportation or gas and car maintenance. These expenses can add up quickly and contribute to the overall higher cost of living in the area.

Other Considerations

While the cost of living is certainly an important factor to keep in mind, there are other things you might want to consider as well. For example:

  • Utilities: The cost of utilities can vary depending on where you live and what type of housing you have. You might need to pay for electricity, water, gas, trash collection, and other necessary services.
  • Entertainment: While it’s definitely possible to find free or low-cost entertainment options in Costa Mesa, you may also want to budget for things like movies, concerts, and other experiences that can add to your overall quality of life.
  • Taxes: Depending on your income and other factors, you may need to pay local taxes such as property tax, sales tax, and income tax. Be sure to research these costs ahead of time so you can budget accordingly.

Overall, while Costa Mesa can certainly be an expensive place to live, it’s also possible to find ways to save money and make it work for your budget. By understanding the potential costs of living in the area and planning ahead, you can make sure that you’re prepared to handle the higher expenses that come with residing in this beautiful Southern California city.

How Much Does It Cost for an ADU?

A common question that homeowners ask when it comes to building an Accessory Dwelling Unit (ADU) is, “how much does it cost?” The answer to this question isn’t straightforward, and it depends on several factors. Below are some of the factors that can influence the cost of building an ADU:

Size and Layout

The size and layout of your ADU affect the cost of construction. The larger the ADU, the higher the cost. The same applies to the layout. Unique layouts that require more work and materials can also increase the cost of construction.

Materials and Finishes

The type of materials and finishes you choose for your ADU can also affect the cost. High-end finishes such as granite countertops, fancy flooring, and expensive appliances will significantly increase the cost of construction.

Labor and Professional Fees

The labor and professional fees charged by your contractor, architect, and other professionals will also contribute to the total cost of construction. The more complex the project, the higher the professional fees.

Permit and Other Fees

Permits and other fees are also an additional cost that homeowners must consider when building an ADU. Permit fees vary from city to city, and they can easily add up, making the overall cost of construction much higher.

Miscellaneous Costs

Other costs that might arise during the construction phase, such as unexpected expenses, delays, or change orders, can also impact the cost.

Key Takeaways

  • The cost of building an ADU varies depending on several factors.
  • Size and layout, materials and finishes, labor and professional fees, permit and other fees, and miscellaneous costs are among the factors that can contribute to the total cost of construction.

In conclusion, it’s essential to have a budget in mind when planning to build an ADU. The cost of construction can be high, but it’s an excellent way to increase the value of your property and generate additional income. Do your research and consult with professionals to get a better understanding of the cost involved in building an ADU.

Costa Mesa ADU Setbacks: What to Expect

If you’re planning to build an ADU in Costa Mesa, setbacks are something you should know. Setbacks refer to the distances between your construction site’s edge and the property line, street, or other buildings. Here are some important things to note about the setbacks for an ADU in Costa Mesa:

1. Consult With the City

Before starting your ADU project, it’s essential to consult with the city and understand the local codes, zoning laws, and setback requirements. This will help you plan your construction within the limits and avoid future issues.

2. Front Yard Setbacks

The city of Costa Mesa has specific requirements for front yard setbacks, depending on your property’s location, zone, and size. Generally, the front setback ranges from 15-25 feet, and it shouldn’t exceed 50% of the lot’s width.

3. Side Yard Setbacks

Just like front setbacks, the city has specific side yard requirements, based on your property’s location, zone, and size. The side setback generally ranges from 3-10 feet, and it shouldn’t exceed 30% of the lot’s width.

4. Rear Yard Setbacks

Costa Mesa’s rear yard setback is between 5-10 feet, depending on your property’s location, zone, and size. If your ADU has an upper-level balcony, deck, or any other feature, the setback could increase.

5. ADU Height limit

The city of Costa Mesa allows ADUs up to 16 feet in height or one-foot taller than the main house’s height, whichever is less. However, certain areas or zones have specific height limits, and it’s essential to consult with the city before starting your project.

6. Reaching the Maximum Floor Area

ADUs have maximum floor area limitations based on your property’s size and zoning. In Costa Mesa, ADUs built on a 7,000 square feet property cannot exceed 1,000 square feet in size. ADUs built on a 10,000 square feet property cannot exceed 1,200 square feet in size.

7. Other Setback Considerations

Other things to consider when constructing your ADU are the utility lines, easements, and fire safety codes. Ensure that your ADU’s distance from power lines, sewer lines, and other utility lines exceed the required setbacks to avoid future safety or structural issues.

In conclusion, knowing the setback requirements for an ADU in Costa Mesa is essential for a smooth project and avoiding future conflicts with the city. Ensure to consult with the local authority before starting your project and adhere to the setback limitations to avoid future legal issues.

How much does it cost to build an ADU in Orange County?

Adding an ADU (Accessory Dwelling Unit) to your property can be an attractive option to create additional living space, generate rental income, or accommodate extended family members. ADUs, also known as granny flats or mother-in-law units, are an excellent way to increase the value of your property and enhance your lifestyle. However, before you dive into building an ADU in Orange County, it is essential to understand the cost involved in the process. Here are some factors that affect the cost of building an ADU in Orange County:

1. Size and Layout

The size and layout of your ADU will significantly impact the overall cost of construction. A larger ADU with more complex designs will require more building materials and labor, resulting in higher costs. Tailoring the design of your ADU to your specific living needs will improve your overall satisfaction with the project.

2. Permits and Building Fees

Before starting construction, you will need to obtain permits and pay several building fees, such as plan check fees, building permit fees, development impact fees, and school fees. The cost will vary, depending on the complexity of the project and the city or county where you plan to build.

costa mesa adu

3. Location

The location of your property is a significant factor when it comes to building an ADU. The cost of materials and labor tends to be higher in certain areas, particularly in upscale neighborhoods and areas with a high cost of living.

4. Site Costs

Site costs refer to the expenses associated with preparing the site for construction, such as excavation, grading, and utility connections. Site costs will vary depending on the level of preparation needed for your specific project.

5. Design Features

The design features you choose for your ADU will also affect the cost. Special features, such as fireplaces, vaulted ceilings, or custom cabinetry, can add significant expenses to the project.

6. Contractor Fees

Finally, you will need to budget for contractor fees, which can vary depending on the level of experience of your contractor and the complexity of the project.

In conclusion, the cost of building an ADU in Orange County will depend on several factors, including the size and layout of the unit, permits and building fees, location, site costs, design features, and contractor fees. On average, the cost of building an ADU in Orange County can range from $50,000 to $250,000 or more. However, with proper planning, research, and budgeting, you can build an ADU that fits your needs and budget.