Costa Mesa ADU Regulations & Building Guide

Costa Mesa is a vibrant city in Southern California known for its unique charm and diverse population. It offers a blend of urban and suburban experiences.

California State ADU Laws

California has some of the most progressive ADU legislation in the country. Recent laws including AB 68, SB 13, and AB 881 have significantly streamlined the ADU approval process and reduced barriers for homeowners.

Key California ADU Regulations:

• Size Limits: Detached ADUs can be up to 1,200 sq ft. Attached ADUs can be up to 50% of the primary dwelling or 1,200 sq ft, whichever is less.
• Setbacks: Minimum 4-foot side and rear setbacks for detached ADUs.
• Height: Generally up to 16 feet, with some exceptions for two-story ADUs (up to 25 feet in certain zones).
• Parking: No additional parking required in most cases, especially near transit.
• Owner Occupancy: No owner-occupancy requirement until 2025 for most ADUs.

Costa Mesa Local Requirements

While California state law provides baseline regulations, Costa Mesa may have additional local requirements. GatherADU's team stays current with Costa Mesa's specific zoning codes, architectural guidelines, and permit processes to ensure your ADU project meets all requirements.

Common local considerations in Costa Mesa include:

• Design review requirements and architectural standards
• Utility connection fees and impact fees
• Fire department access requirements
• Neighborhood-specific overlay zones

California law (AB 68, AB 881, SB 9, and subsequent legislation) guarantees your right to build ADUs. Cities cannot:

• Require owner-occupancy for ADUs permitted after 2020
• Require additional parking for ADUs near transit
• Charge impact fees for ADUs under 750 sq ft
• Deny ADUs that meet state minimum standards
• Impose lot coverage limits that prevent a 800 sq ft ADU

If you believe your ADU application is being unfairly denied, California HCD can intervene on your behalf.

California ADU Legislation Overview

California leads the nation in ADU-friendly legislation. The state has passed numerous laws to encourage ADU construction as a solution to the housing crisis.

Key California ADU Laws:

• AB 68 (2020): Reduced local government review time and expanded ADU construction options.
• SB 13 (2020): Limited impact fees and reduced owner-occupancy requirements.
• AB 881 (2020): Prohibited minimum lot size requirements and allowed JADUs in all zones.
• AB 2221 (2022): Further streamlined the ADU approval process.
• SB 897 (2022): Increased height limits for ADUs in certain zones.

California ADU Benefits:

• Property value increase of 20-30% on average
• Rental income potential of $1,500-$3,500+ monthly
• Housing flexibility for family members
• No owner-occupancy requirements (until 2025)

Costa Mesa, California, is a vibrant city located in Orange County. Known for its dynamic blend of arts, shopping, and dining, Costa Mesa is a central hub in the region with a population of approximately 113,003 residents. The city offers a mix of suburban comfort and urban amenities, making it an attractive place to live.

Geography and History

Costa Mesa is situated about 4 miles inland from the Pacific Ocean and is bordered by the cities of Newport Beach, Huntington Beach, and Irvine. The city was incorporated in 1953 and has grown into a diverse and culturally rich community. Its strategic location between major highways and proximity to the beach contribute to its appeal.

Local Economy

Costa Mesa’s economy is diverse, with several key sectors:

• Retail and Services: Home to South Coast Plaza, one of the largest shopping centers on the West Coast, and numerous dining and entertainment options.
• Arts and Culture: The city boasts a thriving arts scene with venues like the Segerstrom Center for the Arts and various galleries.
• Education: The city is served by the Newport-Mesa Unified School District and is near several higher education institutions, including Vanguard University.
• Healthcare: Includes medical centers such as Hoag Hospital.
• Technology and Business: Hosts a range of businesses and technology firms, contributing to its economic growth.

Popular Neighborhoods

Costa Mesa features several distinct neighborhoods, each with its own character:

• Downtown Costa Mesa: Known for its vibrant arts scene, dining options, and shopping.
• Mesa Verde: A residential area with spacious homes and tree-lined streets.
• Eastside Costa Mesa: Features a mix of older homes and new developments with a strong community feel.
• South Coast Metro: A commercial and residential area known for its proximity to South Coast Plaza and cultural amenities.
• Fairview Park Area: Offers a blend of residential living with access to the park and recreational opportunities.

Real Estate Market

Costa Mesa’s real estate market includes a variety of housing options, from single-family homes to apartment complexes. The market has experienced growth due to the city’s desirable location, amenities, and relatively high quality of life. Recent trends include increased property values and a competitive housing market.

ADU Regulations in Costa Mesa

Costa Mesa’s ADU regulations are designed to accommodate the growing need for additional housing while maintaining the city’s aesthetic and community standards.

• Zoning: ADUs are permitted in residential zones and certain mixed-use zones that allow residential uses.
• Types of ADUs: Both attached and detached ADUs are allowed, as well as Junior ADUs (JADUs) and conversion of existing structures into ADUs.
• Size Limits:
  • Detached ADUs: Up to 1,200 sqft or 50% of the primary dwelling’s living area, whichever is less.
  • Attached ADUs: Up to 50% of the primary dwelling’s living area or 1,200 sqft, whichever is less.
  • JADUs: Up to 500 sqft.
• Height Restrictions: Detached ADUs are generally limited to 16 feet in height, with potential exceptions for certain designs.
• Parking: Generally, no additional parking is required if the ADU is located within a half-mile radius of public transit. In other cases, one additional parking space may be required.
• Owner Occupancy: As of 2020, there is no owner-occupancy requirement for ADUs. However, JADUs do require owner occupancy.
• Approval Process: ADUs meeting specific criteria may benefit from a streamlined approval process, including ministerial review.
• Multiple ADUs: In multi-family properties, up to two detached ADUs are allowed, or ADUs for 25% of the existing units within the structure, whichever is greater.
• Impact Fees: Impact fees for ADUs are typically reduced to encourage development, especially for smaller units.
• Design Standards: ADUs must be designed to be compatible with the primary residence and neighborhood character, including considerations for architectural style and materials.

These regulations aim to address Costa Mesa’s housing needs while preserving the city’s charm and enhancing community development.

Cultural Landmarks and Unique Aspects

Costa Mesa is known for several unique features and landmarks:

• South Coast Plaza: A major shopping destination with luxury brands and a wide range of dining options.
• Segerstrom Center for the Arts: A premier cultural venue hosting a variety of performances, including Broadway shows and concerts.
• OC Fair & Event Center: Hosts the annual Orange County Fair and other community events.
• Costa Mesa Historical Society: Provides insight into the city’s history and heritage through exhibits and events.
• Fairview Park: A large park offering trails, open space, and recreational opportunities.

Costa Mesa’s ADU regulations are designed to meet the city’s growing housing demands while maintaining its vibrant and diverse character. With its strong economy, cultural attractions, and desirable neighborhoods, Costa Mesa offers a high quality of life and a welcoming environment for residents. The city’s approach to ADUs reflects its commitment to providing flexible and affordable housing options while preserving its unique community atmosphere.

‍