ADU Alliance

2023 Guide To ADU Laws In Carlsbad, San Diego County, CA

Over the past decade, the California state legislature has significantly modified Government Code 65852, progressively easing restrictions and making it more feasible for property owners to build Accessory Dwelling Units (ADUs). This comprehensive guide outlines the specific ADU laws in Carlsbad and the regulations applicable.

Key Takeaways:

  • Benefits of ADUs in Carlsbad
  • ADU types allowed in Carlsbad
  • Development standards for ADUs
  • Permit processing steps

To address the pressing housing problem in the state and promote affordable housing, the California legislature acknowledges the significance of ADUs as an essential component of the housing supply. ADUs Laws in Carlsbad offer an alternative to traditional market-rate home construction and can be integrated into existing or proposed homes in various ways, including conversions, additions, or new constructions.

benefits of adu in carlsbad

Benefits of ADUs

  • Low Cost to Build: ADUs require no public subsidy and offer a cost-effective solution, ranging from $10,000 for a simple bedroom conversion to $300,000 for a higher-end unit.
  • Income Generation: ADUs provide a new income stream for property owners, helping supplement mortgage costs on the main home.
  • Environmentally Friendly: With a low carbon footprint, ADUs use fewer resources, making them environmentally sustainable.
  • Flexibility for Changing Households: ADUs cater to the evolving makeup of households, accommodating diverse living space demands.

Key Documents Referenced

  • State law: 65852.2 and 65852.150
  • Health & Safety Code: 18010 and 18009.3
  • Carlsbad Municipal Code: 21.10.030
  • Building Permit Submittal Requirements: B-5
  • California Coastal Zone: Map
  • ADU Parking Replacement Areas: Map
  • Carlsbad and Poinsettia Station Radius Maps: Maps

ADU Types and Development Standards

Types of Accessory Structures

Carlsbad distinguishes between various accessory structures, each with its own set of regulations:

Accessory Dwelling Unit (ADU):

  • Can be attached or detached.
  • Provides complete independent living facilities.
  • Subject to size, height, setback, and zoning standards.

Junior Accessory Dwelling Unit (JADU):

  • A smaller ADU is located within the main single-family home.
  • Maximum size of 500 sq ft.
  • No additional parking is required.

Guest Houses:

  • For property employees or temporary guests.
  • Cannot include a kitchen or wet bar.
  • Not for separate dwellings or rentals.

Park Model Trailers:

  • Not designed for long-term habitation.
  • Distinct from state-certified manufactured homes suitable for ADUs.

adu types in carlsbad

General Development Standards

The permit process under ADU laws in Carlsbad is limited to administrative approval, avoiding discretionary reviews or public hearings. Development standards vary based on the type and location of the ADU proposed.

Development standards for ADUs:

Aspect Requirement
Number of ADUs One attached or one detached per single-family lot; ADU and JADU can coexist.
Existing Main Residence Required on the property, or the ADU must be constructed concurrently with the main residence.
Construction Standards Compliance with California Residential Code for “Efficiency Dwelling Units”

ADU Size Requirements:

  • Attached ADUs: Not to exceed 50% of the total floor area of the existing main residence or 1,200 sq ft, whichever is less.
  • Detached ADUs: Allowed up to 1,200 sq ft, depending on lot coverage allowances.

ADU Height Requirements:

  • Detached ADUs: Limited to a maximum of 16 feet unless specified conditions apply.

ADU Setback Requirements:

  • Attached and detached ADUs: Minimum four-foot setback from rear and side-yard property lines.

Parking Requirements:

  • One parking space is required; exemptions apply based on specific conditions.

Miscellaneous Requirements:

  • Roof decks are not permitted on detached ADUs.
  • ADUs must be rented for a term of at least 30 days.

development standards for adus and jadus

Development Standards for JADUs:

Aspect Requirement
Number of JADUs One JADU is allowed within the walls of a proposed or existing single-family residence.
Owner Occupancy The property owner must occupy either the JADU or the main residence.
JADU Size Maximum of 500 sq ft. No parking is required.

Miscellaneous Requirements:

  • JADUs must be rented for a term of at least 30 days.

Development Standards for Certain ADU Types

The state has established categories of ADUs subject to fewer zoning and development standards. These include

  • Multi-family ADUs:
    • Conversion of non-livable space within existing multi-family structures.
    • Maximum number based on existing units.
    • Detached ADUs are allowed with specific conditions.
  • Mandatory-ADUs:
    • Maximum size of 800 sq ft.
    • Maximum height is based on zone and location.
    • One mandatory ADU and one JADU are permitted per lot within a single-family home.

ADU Laws in Carlsbad: Permit Processing

ADU laws in Carlsbad state that a residential building permit application is required. The process involves submitting required documentation, undergoing plan review, and scheduling inspections. The city aims to approve or deny an application within 60 days of its completion, unless an extension is requested.

permit process in carlsbad

Coastal Development Permit Application

  • Proposed ADUs within the California Coastal Zone require a Minor Coastal Development Permit (MCDP). However, the attached ADUs and JADUs outside the Coastal Appeal Zone only need the approval of a building permit application as per ADU laws in Carlsbad.

Permit Application Fees

  • All applicable plan check and inspection fees apply. ADU laws in Carlsbad grant that for less than 750 sq ft, no impact fees are charged. Fees for larger ADUs are proportionate to the primary dwelling unit’s square footage. Utility connection fees may also apply based on the ADU’s square footage.

For projects requiring a building permit, contact ADU Alliance at (760) 456-8747 or via email at

By understanding and adhering to these comprehensive ADU laws in Carlsbad, property owners in Carlsbad can navigate the ADU permitting process more efficiently, ensuring compliance with regulations and fostering the creation of additional housing options. For further details and assistance, feel free to visit our website at: