Carlsbad ADU Information Bulletin IB-111

Accessory Dwelling Units IB-111 Over the past decade, the state legislature has made Documents Referenced several modifications to California Government Code City of Carlsbad Accessory Dwelling Units Webpage Title 7, Division 1, Chapter 13 §66310-66342 (previously State ADU law; §66310-66342 Gov. Code §65852.2;-.22; and -.26) progressively making HCD; ADU Handbook it easier for property owners to build accessory dwelling Health & Safety Code; §17958.1, §18010 & §18009.3 units, often called ADUs. Carlsbad Municipal Code Title 21; §21.10.030 California Coastal Zone; Map ADU Parking Replacement Areas; Map Transit Stations – ½ Mile Walking Distance Maps North County Transit Station Website Building Permit Application Form; B-1 Minor Coastal Development Permit; P-6 Permit-Ready ADU Checklist; B-75 Permit-Ready ADU Program Webpage Cal HFA ADU Grant Program Website rate home construction. ADUs can be integrated into existing or proposed homes in a variety of ways, This Info-Bulletin outlines the city’s development including converting a portion of an existing house,

requirements for new ADU construction and has been adding to the existing house, converting an existing updated to include recent bills including AB 2221 and SB garage, storage area, studio or other accessory 897, effective Jan. 2023; AB 976, AB 1033, and AB 1332, building, or constructing a new detached structure. effective Jan. 2024; SB 477, effective March 2024; AB Development of ADUs offers many benefits, a few of 2533 and SB 1211, effective Jan. 2025. which are reflected below. Considering the constantly evolving laws affecting ADUs, Low Cost to Build the CA Department of Housing and Community ADUs require no public subsidy and cost anywhere Development (HCD) publishes a useful ADU Handbook from $10,000 for a simple bedroom conversion to that provides information on the most recent and relevant changes and interpretations of ADU laws. $300,000 for a higher-end companion unit. HCD’s resource guide should be used as a supplement to Provides Income to Homeowners this Info-Bulletin. ADUs help create a new income stream for property

BACKGROUND owners, which can help supplement mortgage costs on the primary home. The state faces a serious housing problem that not only threatens its economic security, the lack of access to Environmentally Friendly affordable housing can have a direct impact upon the ADUs have a low-carbon footprint, using less water, health, safety, diversity, and welfare of Carlsbad electricity, and construction materials. A detached residents. ADU can save 26,000 pounds of CO2 emissions a year To retain a healthy livable environment and meet state compared to a single-family dwelling. mandated housing goals, more needs to be done to Flexibility for Changing Households accommodate locally available and affordable housing stock. This will require implementing multiple housing The makeup of today’s household is rapidly changing. programs to meet housing demands. Many families are now made up of single/aging parents or extended families who do not require large Pursuant to Govt. Code §66310, the state legislature living spaces. ADUs are often better suited to meet the

found and declared that ADUs are an essential living space demands associated with this new shift in component of the state’s housing supply and family structure. provide an alternative option to traditional market- Community Development Department | 1635 Faraday Ave. | Carlsbad, CA 92008 | www.carlsbadca.gov

be located within the primary single-family home with a TYPES OF ACCESSORY STRUCTURES separate entrance. An efficiency cooking area is required to Development requirements for an ADU will vary be provided within the unit. It may include independent depending upon where the unit is constructed on the sanitation within the unit or shared facilities with the existing property. More information about this is covered residence. No additional parking is required for a JADU. under the “General Development Standards” section of this bulletin. But before jumping ahead, it is Guest Houses important to understand that not all accessory structures are considered ADUs, and some structures must meet minimum standards to qualify as an ADU. Accessory Dwelling Unit A guest house is a type of accessory structure for the sole use of people employed on the property or temporarily used by guests of the primary home. Essentially, a guest house acts as an extra bedroom to the primary home. As such, a guest house cannot include a kitchen or wet bar and cannot be rented or used as a separate dwelling unit.

ADUs have many different names --- granny flats, in- Park Model Trailers law units, backyard cottages, and secondary units just to name a few. Despite the name, an ADU is a residential dwelling unit that provides complete independent living facilities for one or more people. An ADU includes permanent provisions for living, sleeping, eating, cooking and sanitation. An ADU may be attached to or detached from the primary dwelling, integrated into existing or a proposed single-family home or multi-family residences, or created by converting existing space such as a garage. Junior Accessory Dwelling Unit Park model trailers, sometimes referred to as “tiny homes,” have been marketed as an inexpensive alternative to conventional ADU construction. Park model trailers are not designed for long-term habitation. CA Health & Safety Code §18010 & §18009.3 define park model trailers as recreational vehicles. While they may look more like a manufactured home and less like an RV, park model trailers are not certified by HCD as meeting the minimum health and safety standards for permanent housing.

However, the manufactured homes that you often find in a “mobile home park” are state HCD certified and can be used as an ADU. A Junior Accessory Dwelling Unit (JADU) is an ADU, but smaller in size with unique development standards; the most significant being that JADUs must Page 2 of 8 IB-111_Accessory Dwelling Units Oct. 2025

• Existing nonconforming ADUs or JADUs constructed before GENERAL DEVELOPMENT STANDARDS Jan. 1, 2020, shall be permitted, unless conformance is Per state law, permitting an ADU is limited to an necessary to protect the health and safety of the public, administrative approval process --- no discretionary resident and/or occupant, or if the building is deemed review, CEQA environmental analysis, or public substandard by the building official (Gov. Code §66332). hearings --- the city can only apply clearly defined objective development standards (e.g., parking, • ADUs shall comply with the construction standards of the setback, size, height, landscaping, etc.). However, the California Residential Code for an “Efficiency Unit.” As applicable development standards that get applied to required pursuant to Gov. Code §66313 and defined by Health an ADU varies depending upon the type and location of & Safet Code §17958.1. Key building construction standards the ADU proposed. This makes implementing state worth noting: ADU law, a bit challenging. o ADUs must have a separate entrance from the

primary residence. An internal connection for attached ADUs is optional. o ADUs must contain complete independent living facilities, including a permanent kitchen and areas for living and sleeping. o New detached ADUs shall include the installation of a solar photovoltaic system unless an existing onsite system has the capacity to provide for the ADU. o Fire sprinklers are not required for an ADU unless previously required when the primary home was constructed. • ADUs shall comply with all applicable zoning code standards, with the following exceptions: o Detached ADUs that are ˃800 square feet in size or attached ADUs that are ˃800 square feet in size and ˃16 feet in height are subject to maximum lot The following sections have been created to help coverage requirements. No ADU is subject to applicants navigate ADU development standards. minimum lot size requirements. o Adequate water and sewer services shall be readily • Development Standards for ADUs available; Upgrades to existing services may not be • Development Standards for JADUs required.

• Development Standards for Certain ADU Types o Size requirements o Multiple-family & Two-family Dwelling ADUs  Attached ADUs that include new construction o Mandatory-Approval ADUs shall not exceed 50% of the total floor area of Development Standards for ADUs the existing primary residence, or 1,200 square feet in size, whichever is less but no less than 800 The following development standards apply to all ADUs, sq. ft. whether attached or detached.  Converted ADUs contained entirely within the • One attached or one detached ADU is allowed on a single-family residence, or existing accessory single-family residential lot; not both with the structure cannot exceed the total square footage exception for certain ADU Types as further of the primary residence subject to the discussed below in this Info-Bulletin. applicable zone. However, up to 150 square feet Notwithstanding, an ADU and a JADU can both be on the same property. The property must have an existing primary residence; or the ADU must be constructed concurrently with the primary residence. IB-111_Accessory Dwelling Units Oct.

to accommodate ingress and egress is allowed (CMC 21.10.030.E.1).  Detached ADUs are allowed up to 1,200 square feet in size depending on lot coverage allowances. o Height requirements  Detached ADUs are limited to max. one story and 16 feet in height, unless located: - Above or below a one-story detached garage then the detached ADU must conform with the applicable height limit of the zone but not to exceed one story above or below the one-story garage. - On a lot with an existing or proposed Coastal Zone and non-conforming conditions impact multistory two-family or multistory to coastal resources (geologic setback, public view multiple-family dwelling, the ADU shall encroachment, coastal access, or habitat preserve be allowed 18 feet in height. buffers). - On a lot with an existing or proposed  Setbacks for new ADU can conform to those of a single family, two-family or multiple- legally demolished structure that it will replace, family dwelling unit that is within one- provided that the construction of the proposed ADU

half mile walking distance of a major is built in the same location and to the same transit stop (Carlsbad Village Station or dimensions. Poinsettia Station), then a height of 18  In the Coastal Zone, an ADU or JADU that results feet is allowed. An additional two feet from new construction, or expanding or converting in height (max. 20 ft.) is allowed to an existing structure, shall comply with the accommodate the ADU roof pitch to requirements of the Coastal Act by extension of the align with the roof pitch of the primary Local Coastal Program (LCP). If there is a conflict dwelling (see Transit Stations ½ Mile with state government code ADU regulations and Walking Distance Maps). the LCP, the LCP shall apply.  Attached 1- or 2- story ADUs are allowed up  Accessory uses not required for ADUs – garages, to 25 feet in height, or subject to the limits patio covers, decks, etc. – must meet standard specified under the applicable zone but not zoning setbacks and cannot observe four-foot side to exceed two stories. and rear- yard setbacks. o Setback requirements o Parking requirements

 Attached and detached ADUs shall maintain  One parking space shall be required, which may be a minimum four-foot setback from rear and located within the building setbacks or in an existing side-yard property lines. driveway as tandem parking.  Front yard setback and required building  A parking space is not required for an ADU if the separation requirements are per applicable property meets any one of the following: zoning standards and building code standards, respectively, provided the front yard setback - Located within one-half mile walking distance of does not preclude an ADU of at least 800 public transit stop (e.g. Carlsbad Village Station, square feet (see Mandatory-Approval ADUs Poinsettia Station or bus stops) per Government Section below). Code §66322(a)(1) (see Transit Stations ½ Mile Walking Distance Maps and for bus stop locations  Existing setbacks can be maintained for an visit https://gonctd.com). existing non-conforming detached garage or existing accessory structure that is converted - Located within a historic district.

to an ADU, unless the project is within the - Constructed as part of a proposed or existing Page 4 of 8 IB-111_Accessory Dwelling Units Oct. 2025

residence or accessory structure. permit prior to Jan. 1, 2020, are exempt from this requirement. - Located within one block of a dedicated car share lot.  ADUs are exempt from owner-occupancy requirements. - When on-street parking permits are required but not offered to the occupant  Pursuant to Civil Code §4751(a), private restrictions of the accessory dwelling unit. such as Conditions, Covenants and Restrictions (HOA CC&Rs) can no longer prohibit the - When there is a car share vehicle located construction and renting of ADUs. See the State’s within one block of the accessory HCD handbook for more information. dwelling unit.  The city does not permit separate sales of ADUs.  Parking spaces do not need to be replaced Although state law (Gov. Code §66341) allows an when a garage, carport, covered parking exception for qualified nonprofits such as affordable structure or uncovered parking space is housing organizations (see Gov. Code §66341), the demolished and/or converted into an ADU city has not enacted the required city ordinance to (Gov. Code §66314), except for certain

opt into this expanded state option (Gov. Code locations located within the Parking §66342). Replacement Areas Map. In the Coastal Zone, uncovered parking spaces demolished and/or Development Standards for JADUs converted into an ADU does still require a The following standards apply to all JADUs. replacement. • One JADU is allowed to be constructed within the walls of a proposed or existing single-family residence or attached garage. Additions or modifications to an existing residence for the purpose of building a JADU are allowed. • An ADU and a JADU can be constructed on the same lot when a detached ADU or ADU conversion is proposed. • The property owner must occupy either the JADU or the primary residence. In cases where both an ADU and JADU are constructed; the owner can live in one of the three units. • JADUs shall comply with ALL zoning code standards applicable to the primary residence, with the following exceptions: o The JADU shall be a max. 500 square feet in size. o No parking is required for a JADU. o JADUs shall comply with the standards of the

California Residential Code. Key building o Miscellaneous Requirements construction standards worth noting:  Roof decks are not permitted on detached  An efficiency unit kitchen is required. ADUs.  A separate entrance from the primary residence  The exterior roofing, trim, walls, windows, is required. and color palette of the ADU shall incorporate  An internal connection is optional unless a the same features as the primary dwelling restroom is shared with the primary residence unit or for lots with multiple units, the in which case an internal connection is nearest dwelling unit as measured from the required. wall of the dwelling unit building to the  Having a separate water, sewer or power nearest wall of the proposed ADU. connection from the existing primary residence  ADUs shall only be rented for a term of at is not required. least 30 days however, ADUs within the  Fire sprinklers are not required for a JADU Coastal Zone that were issued a building IB-111_Accessory Dwelling Units Oct. 2025 Page 5 of 8

unless fire sprinklers were required areas that can be converted include storage rooms, when the primary home was basements, and garage spaces. constructed. o Multiple detached single-family dwelling units located • Miscellaneous Requirements on one lot are not by definition a multiple-family or two- family dwelling unit. o The exterior roofing, trim, walls, windows, and color palette of the JADU o The maximum number of ADUs converted from the non- shall incorporate the same features as livable space of a multiple-family dwelling building is the primary dwelling unit. equal to 25% of the total number of existing multiple- family dwelling units in the structure. o JADUs shall only be rented for a term of at least 30 days. JADUs located in the  Fractional units are rounded down. Coastal Zone that were issued a building  A minimum of one converted ADU is allowed. permit prior to Jan. 1, 2020, are exempt o Outside the Coastal Zone: from this requirement.  Maximum two (2) detached ADUs are o Pursuant to Civil Code §4751(a), private allowed on a lot that has a proposed

restrictions such as Conditions, Covenants multiple-family or proposed two-family and Restrictions (HOA CC&Rs) can no longer dwelling; or prohibit the construction and renting of JADUs.  Maximum eight (8) detached ADUs are allowed on a lot that has an existing multiple-family dwelling or two-family dwelling (GC §66323).  The total number of detached ADUs for both scenarios above shall not exceed the number of primary dwelling units. o In the Coastal Zone: Up to two (2) detached ADUs are allowed on a lot that has an existing or proposed multiple-family dwelling or two-family dwelling (CMC §21.10.030.D). The total number of detached ADUs shall not exceed the number of primary dwelling units. o See “Development Standards for ADUs” above for height and setback requirements (Gov. Code §66323 and CMC §21.10.030.E). Development Standards for Certain ADU Types o Two detached ADUs may be attached to each other. Pursuant to Gov. Code §66323, the state established o HOA authorization is required for ADUs proposed in four categories of ADUs that are not subject to any condominium common areas.

other specified areas of ADU law, most notably • Mandatory-Approval ADUs zoning, design and development standards. However, o Converted or detached ADUs located within and ADUs authorized under this code section must still outside of the Coastal Zone shall receive mandatory meet the building code and health and safety approval if it meets the following requirements: requirements and the Coastal Act. Because of overlapping similarities, the four categories have been o Converted ADUs must be: combined into two ADU types: Multiple-/Two-family  Within the existing or proposed space of the Dwelling Unit ADUs and Mandatory-Approval ADUs. single-family residence or accessory structure ADUs meeting the limited standards described below shall be allowed by right.  Have space for exterior access from the single- family dwelling • Multiple-family & Two-family Dwelling Units ADUs  The side and rear setbacks are sufficient for fire o Non-livable space within an existing multiple- and safety requirements. family dwelling or two-family dwelling building may be converted into an ADU. Examples of

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o Detached ADUs must be: permit approvals (apart from the ADU approval), depending on the existing and proposed site conditions.  Maximum 800 sq. ft. For example, if a retaining wall is needed, this may  Min. four-foot side and rear yard setbacks require a structural load analysis. Please check with city  May protrude into the front yard setback staff for further information prior to submittal. of the zone when demonstrated there is • The city will approve or deny an application within 60 no other alternative to allow for days from the date the application was deemed construction of a max. 800 square foot complete unless the applicant requests an extension of ADU with four-foot side and rear yard time. setbacks (CMC §21.10.030.E). Coastal Development Permit Application o Pursuant to Gov. Code §66323, a single-family residential lot may be developed with one The following permitting steps shall apply to processing a CDP converted and one detached “mandatory- for projects within the Coastal Zone.

approval” ADU and one JADU (a total of two • All proposed ADUs located within the California Coastal (2) ADUs and one (1) JADU). Zone require a Minor Coastal Development Permit o See “Development Standards for ADUs” (MCDP) (Form P-6). above for height requirements. o The following are exempt from requiring a MCDP: Attached ADUs and JADUs --- these only require approval of a building permit application, however, with a few exceptions (see CMC §21.201.060(B)(1) for more information). • A public hearing shall not be required to approve an ADU. Neighboring property owners will still be notified of the permit application pursuant to city code but permit approval will be done administratively by the City Planner. • The City Planner’s decision can be appealed directly to the California Coastal Commission. Permit Application Fees • All applicable plan check and inspection fees apply. However, no impact fees are charged for development of an ADU that is less than 750 square feet. There may be other “non-impact” fees by special districts or local PERMIT PROCESSING STEPS

agencies (e.g., school districts). The section below provides the required permit • Impact fees for an ADU more than 750 square feet are applications and general processing steps to secure charged proportionately in relation to the square necessary approvals for an ADU or JADU (collectively footage of the primary dwelling unit. (e.g., if you have referred in this section as “ADUs”). The permit a proposed 1,000 square feet ADU, and you have an application submittal must include all required existing 2,000 square foot primary dwelling unit, you information for the packet to be accepted and would be charged 50% on an equivalent basis). For an processed. ADU on a lot with a multiple-family or two-family Building Permit Application dwelling, the proportionality shall be based on the average square footage of the units within that • All ADUs are required to submit a residential multiple-family or two-family dwelling structure. building permit application and required supporting documentation (see Form B-1). • A new utility connection may be required, and

connection fees and capacity charges are based upon • All ADUs proposed as part of a remodel/new either the ADU’s square feet or the number of its primary dwelling unit shall follow the permit process drainage fixture unit values, as defined by the timeline of the permit for the primary dwelling unit. California Plumbing Code. Utility connections and fees • The project site may require other types of shall not be required for ADU/JADUs converted from IB-111_Accessory Dwelling Units Oct. 2025 Page 7 of 8

the existing space of a home, including To view all the pre-approved ADU plan sets and for all other expansions of 150 square feet. information about the Permit Ready ADU program, please visit the Program webpage. STATE ADU GRANT PROGRAM The California Housing Finance Agency (Cal HFA) accepts applications for the ADU Grant Program, which provides up to $40,000 towards pre-development and non-recurring closing costs associated with the construction of the ADU. Predevelopment costs include site prep, architectural designs, permits, soil tests, impact fees, property survey, and energy reports. To qualify: • Applicants must own a single-family home or 2-4 units on the site where the ADU will be developed. • Applicants must be income-qualifying households that are low-income (80% of Area Median Income) earning less than $93,440. • Applicants must receive a construction loan through a certified lender to apply for the grant. For more information regarding the Cal HFA grant program, please visit their webpage. YOUR OPTIONS FOR SERVICE

For more information regarding ADU development in the City of Carlsbad, please visit the ADU webpage. PERMIT-READY ADU PROGRAM To apply for a building permit, or building permit questions, In response to state housing laws, the city has created its please contact the Building Division at 442-339-2719 or first ever Permit Ready Accessory Dwelling Unit Program Building@carlsbadca.gov. which is envisioned to encourage the construction of For Coastal Development Permits, or planning /zoning related ADUs by offering property owners a selection of pre- questions, please contact the Planning Division at 442-339-2610 approved detached one-story ADU building plans. Use of or Planning@carlsbadca.gov. these plans will save an applicant time and money by avoiding initial design and review costs and help streamline the building review process. All applicants can use the pre-approved ADU plans, however, they must select the architectural style that matches closest to the colors and materials of the primary residence, or if located on a multiple-family

or two-family residential lot, the closest residential building on the lot. Conceptual drawings of some of the pre-approved ADU building plans are shown on this page. The city is offering four ADU sizes (studio, one-bedroom, two- bedroom, and three-bedroom) and three architectural styles (Spanish, Farmhouse and Modern). Any modifications to the pre-approved building plans must be conducted by a qualified professional and will require full plan review as with a custom ADU (see Permit-Ready ADU Checklist, Form B-75). Page 8 of 8 IB-111_Accessory Dwelling Units Oct. 2025