Frequently Asked Questions

HCD uses the term “66323 Units” to refer to ADUs and JADUs that are created pursuant to Government Code section 66323. They have also been referred to as “State mandated” or “State exempt” ADUs. Government Code section 66323 creates four categories of ADUs (and JADUs) that must be approved ministerially and are not subject to standards set forth in Government Code sections 66314-66322. For example, 66323 Units do not have to comply with lot coverage, front setbacks, and design standards. However, these ADUs must comply with building code and health and safety requirements for dwellings. The four categories are:

1. Single-Family Converted ADUs and JADUs

One ADU per lot is permitted within the converted space of a proposed or existing single-family dwelling or accessory structure. This type of ADU must have exterior access and setbacks for fire and safety but is not subject to a four-foot side and rear yard setback. (Gov. Code, § 66323, subd. (a)(1).)

ADUs converted from accessory structures are eligible for a 150 square-foot expansion to accommodate ingress and egress. For example, if a second story from a single-family dwelling is converted into an ADU, a stairwell of not more than 150 square feet could be added, among other types of ingress and egress configurations that comply with the local building code. (Gov. Code, § 66323, subd. (a)(1)(A).)

In addition, one JADU per lot is permitted within the proposed or existing space of a single-family dwelling or accessory structure and must have exterior access, side and rear setbacks for fire and safety. (Gov. Code, § 66323, subd. (a)(1).) JADUs must also comply with the provisions of JADU Law found in Government Code sections 66333-66339. For the purposes of constructing a JADU, attached garages are part of a single-family dwelling. (Gov. Code, § 66333, subd. (d).) For more information, please see the Handbook section on JADUs.

2. Single-Family Detached ADUs

One detached new construction ADU that does not exceed four-foot side and rear yard setbacks is permitted on lots with an existing or proposed single-family dwelling (Gov. Code, § 66323, subd. (a)(2)). The maximum unit size is 800 square feet with a height limitation of 16, 18, or 20 feet depending on conditions specified in Government Code section 66321, subdivision (b)(4). (Gov. Code, § 66323, subd. (a)(2)(B).)

3. Multifamily Converted ADUs

ADUs may be created within the portions of existing multifamily structures that are not used as livable space (Gov. Code, § 66323, subd. (a)(3)(A)). Local agencies shall allow at least one ADU within an existing multifamily dwelling and up to 25 percent of the existing multifamily dwelling units (Gov. Code, § 66323, subd. (a)(3)(B)). Examples of structures that are not used as livable space include, but are not limited to: storage rooms, boiler rooms, passageways, attics, basements, or garages (Gov. Code, § 66323, subd. (a)(3)(A)).

4. Multifamily Detached ADUs

Up to two detached ADUs are allowed on a lot that has a proposed multifamily dwelling, or up to eight detached ADUs are allowed on a lot with an existing multifamily dwelling, not to exceed the number of existing units on the lot. These ADUs are subject to four-foot rear and side yard setbacks and height limits of 16, 18, or 20 feet depending on conditions specified in Government Code section 66321, subdivision (b)(4). (Gov. Code, § 66323, subd. (a)(4)(A).) A local agency may not require that a setback be modified for an existing multifamily dwelling with setbacks less than four feet as a condition of ADU application approval (Gov. Code, § 66323, subd. (a)(4)(B)).

The local agency must allow the four categories of ADUs listed above to be combined as allowed by the site and lot conditions. For example, pursuant to Government Code 66323, subdivision (a), local governments must allow units created pursuant to subparagraphs (1) and (2) together or (3) and (4) together.

This means that on single-family lots, local agencies must allow at least one ADU constructed from existing space, one JADU, and one newly constructed detached ADU. For multifamily lots, local agencies must permit at least one ADU constructed from existing non-livable space (or up to 25 percent of the number of multifamily units), and two detached ADUs.

A local agency may not impose development or design standards, including both local standards and standards found in State ADU Law, on 66323 Units that are not specifically listed in Government Code section 66323. (Gov. Code, § 66323, subds. (a), (b).) This includes, but is not limited to, parking, height, setbacks, or other zoning provisions (e.g., lot size, open space, floor area ratio, etc.).

Additionally, rentals of 66323 ADUs must be for terms longer than 30 days. (Gov. Code, § 66323, subd. (e).) Fire sprinklers are not required for the ADU if not required for the primary residence, and the construction of an ADU may not trigger the requirement for fire sprinklers in an existing multifamily dwelling. (Gov. Code, § 66323, subd. (d).)

A limit on the number of bedrooms could be construed as a discriminatory practice towards protected classes, such as familial status, and would be considered a constraint on the development of ADUs (Gov. Code, § 65008). Building code standards for minimum bedroom size still apply.

A limit on the number of bedrooms could be construed as a discriminatory practice towards protected classes, such as familial status, (Gov. Code, § 65008) and could also unreasonably restrict the ability of homeowners to create ADUs (Gov. Code, § 66311). Building code standards for minimum bedroom size still apply.

An ADU application pursuant to Government Code section 66314 may be denied due to building code violations on the primary unit only if the violations present a threat to public health and safety and are affected by the construction of the ADU (Gov. Code, § 66322, subd. (b)). However, all ADUs must comply with building code and health and safety requirements for dwellings.

Yes. ADU laws apply to jurisdictions in the California Coastal Zone, but do not alter or lessen the effect or application of Coastal Act resource protection policies (Gov. Code, § 66329). Coastal localities should seek to harmonize the goals of protecting coastal resources and addressing housing needs of Californians. For example, where appropriate, localities should amend Local Coastal Programs for California Coastal Commission review to comply with the California Coastal Act and new State ADU Laws.

For more information, see the California Coastal Commission 2020 Memo and reach out to the local Coastal Commission district office.

No. A local agency cannot impose a deed restriction on an ADU. Government Code section 66315 states, “Section 66314 establishes the maximum standards that a local agency shall use to evaluate a proposed accessory dwelling unit on a lot that includes a proposed or existing single-family dwelling. No additional standards, other than those provided in Section 66314, shall be used or imposed, including an owner-occupant requirement, except that a local agency may require that the property may be used for rentals of terms 30 days or longer.” Section 66314, subdivision (b)(1) allows for local objective standards, but the examples provided all relate to design and development standards (e.g., parking, height, setback, landscape, maximum size of a unit). A deed restriction is not such a standard and thus cannot be imposed.

Yes. A local agency may adopt an ordinance for the creation of JADUs (Gov. Code, § 66333). That ordinance must “[r]equire the recordation of a deed restriction” that includes only a prohibition on the sale of the JADU separate from the sale of the single-family residence and a restriction on the size and attributes of the JADU that conforms with state law (Gov. Code, § 66333, subds. (c)(1), (c)(2)).

Impact fees charged for the construction of ADUs must be determined in accordance with the Mitigation Fee Act and include any monetary exaction other than a tax or special assessment that is charged by a local agency in connection with the approval of an ADU for the purpose of defraying all or a portion of the cost of public facilities relating to the ADU. (Gov. Code, §§ 66324, subd. (a); 66000.) A local agency, special district, or water corporation shall not consider ADUs as a new residential use for the purposes of calculating connection fees or capacity charges for utilities, including water and sewer services. However, these provisions do not apply to ADUs that are constructed concurrently with a new single-family home. (Gov. Code, § 66324, subds. (b), (d).)

No. An ADU is exempt from incurring impact fees from local agencies, special districts, and water corporations if it is less than 750 square feet. If an ADU is 750 square feet or larger, impact fees shall be charged proportionately in relation to the square footage of the ADU to the square footage of the primary dwelling unit. (Gov. Code, § 66324 subd. (c)(1).) In this specific instance, impact fees also include Quimby fees specified in Government Code section 66477 (Gov. Code, § 66324 subd. (c)(2)).

For ADUs that include a 150 square-foot exterior expansion, the 150 square feet count towards the 750 square-foot limit. For example, a 700 square-foot interior conversion ADU with 23 a 150 square-foot exterior expansion for ingress and egress would count as an 850 squarefoot ADU for the purposes of calculating fees, thus triggering the proportionate fee requirement of Government Code section 66324, subdivision (c).

Only when sprinklers are required for the existing primary residence. Installation of fire sprinklers shall not be required in attached, detached, or converted ADUs if sprinklers are not required by building codes for the existing primary residence. For example, a detached singlefamily home designed and constructed decades ago would not have been required to have fire sprinklers installed under the applicable building code at the time. However, if the same primary dwelling recently underwent significant alteration and is now required to have fire sprinklers, any ADU created after that alteration must be provided with fire sprinklers. Additionally, the construction of an ADU under this code section shall not trigger a requirement for fire sprinklers for the primary residence. Finally, if a primary dwelling currently does not have fire sprinklers, and an attached ADU is proposed which would trigger fire sprinkler requirements due to the increase in livable space, that requirement shall not be imposed upon the primary dwelling unit. (Gov. Code, §§ 66314, subd. (d)(12); 66323, subd. (d).)

Possibly. While at the time of this writing the funds have been exhausted, the California Housing Finance Agency’s (CalHFA) ADU Grant Program provided up to $40,000 in assistance to reimburse qualifying homeowners for predevelopment costs necessary to build an ADU or JADU on a lot with an owner-occupied single-family dwelling unit. The ADU Grant Program was intended to create more housing units in California by providing a grant to reimburse qualifying homeowners for predevelopment costs. Predevelopment costs include, but are not limited to, architectural designs, permits, soil tests, impact fees, property surveys, and energy reports.

Some local agencies are creating funding opportunities for ADU/JADU predevelopment and construction costs, or they are waiving fees.

For local agencies wanting to apply for funding for ADUs and JADUs, some of HCD’s funding programs, such as the CalHome Program, the Permanent Local Housing Allocation program, the Prohousing Incentive Program, and the Local Housing Trust Fund Program, do include funding for these housing types as eligible activities.

For more information on local and state funding opportunities for ADU/JADU predevelopment or construction, or funding options for local agencies, please see the Grants and Funding section of our ADU webpage: https://www.hcd.ca.gov/policy-and-research/accessory-dwelling-units.

The Federal Housing Administration (FHA), Freddie Mac, and Fannie Mae also provide loans to support ADUs. The links below include information on these finance programs, including relevant definitions and criteria.

FHA

The FHA recently expanded access to mortgage financing for homes that have or will include ADUs. Specifically, the updated loan policies allow for the inclusion of rental income from the ADU in the borrower’s qualifying income and would allow more borrowers to qualify for FHA financing for properties with ADUs. This includes the 203(k) Rehabilitation loan. Note that the 203(k) Rehabilitation loan may only be used to construct an attached ADU.

For more information on the updated policies, please reference the FHA Single Family Housing Policy Handbook at https://www.hud.gov/sites/dfiles/OCHCO/documents/40001-hsghupdate15-052024.pdf, or the 2023 Mortgagee Letter that includes specific ADU finance changes in the handbook https://www.hud.gov/sites/dfiles/OCHCO/documents/2023- 17hsgml.pdf. Interested parties should look to HUD’s website for any updates.

Freddie Mac

Freddie Mac now offers several options for adding an ADU to an existing home and financing a purchase with the intention to rent or build an ADU. This includes allowing rental income from ADUs to be included in qualified income for a loan.

For more information, please visit https://sf.freddiemac.com/docs/pdf/fact-sheet/adu-factsheet.pdf.

Fannie Mae Fannie Mae now offers financing options for adding an ADU to an existing property, building a home with an ADU using Construction-to-Permanent Financing, and buying a home with an existing ADU.

For more information, please visit https://singlefamily.fanniemae.com/originatingunderwriting/mortgage-products/accessory-dwelling-units.

There is no height limit contained in State ADU Law, but local agencies may impose height limits pursuant to Government Code section 66321, subdivision (b)(4). A local agency may impose a height limit by adopting a compliant ADU ordinance.

A local agency may not impose a height limit that is less than the following:

Detached ADUs

16 feet on a lot with a proposed or existing single-family or multifamily dwelling unit (Gov. Code, § 66321, subd. (b)(4)(A)).

18 feet on a lot with an existing or proposed single-family or multifamily dwelling, including an additional 2 feet to accommodate roof pitch that aligns with the primary dwelling, when the lot is a half-mile from a major transit stop or high-quality transit corridor (Gov. Code, § 66321, subd. (b)(4)(B)). Please see the ADU Glossary for definitions of these terms.

18 feet height on a lot with an existing or proposed multifamily, multistory dwelling (Gov. Code, § 66321, subd. (b)(4)(C)).

If a detached two-story ADU can be built according to the height allowances required under State ADU Law while remaining compliant with the building code, a local agency cannot deny an ADU application to create a two-story ADU, irrespective of the underlying zoning that might restrict a primary dwelling to one story. (Gov. Code, §§ 66321, subd. (b)(4)(D); 66314, subd. (d)(8).)

Attached ADUs

25 feet or the height limitation that applies to the primary dwelling in the local zoning ordinance, whichever is lower (Gov. Code, § 66321, subd. (b)(4)(D)).

No. Sections 714.3 and 4751 of the Civil Code nullify covenants, conditions, and restrictions (CC&Rs) that either effectively prohibit or unreasonably restrict the construction or use of an ADU or JADU on lots zoned to permit single-family residential uses. Such CC&Rs, including operating rules, are void and unenforceable. Applicants who encounter prohibitions of ADUs and JADUs within CC&Rs, whether implicit or explicit, are encouraged to reach out to their local agency

HOAs may impose some limited objective standards on an ADU or JADU, such as requiring, within reason, specific materials, architectural styles, or other design and aesthetic restrictions. However, these standards may not be more stringent than State ADU Law and thereby unreasonably increase the cost to construct or effectively prohibit or extinguish the ability to create or serve an ADU or JADU. (Civ. Code, § 714.3, subd. (b).)

Examples of effective prohibitions, unreasonable costs, and extinguishments of the ability to construct an ADU or JADU may include, but would not be limited to:

• Any delay in reviewing an ADU or JADU for compliance with reasonable restrictions beyond the timeframes required of local agencies (60 days) or that significantly delay the construction or use of an ADU or JADU.

• Requiring alteration to an ADU or JADU application that would cause the property owner to incur substantial costs or forgo the development.

• Imposing a condition that would necessitate re-applying or amending a building permit application that substantially complies with State ADU and JADU Laws.

• Mandating neighboring property owners’ approval or agreement for an ADU or JADU application or considering any disapproval or disagreement to the construction or use of an ADU or JADU by the neighbors as part of the local agency’s ministerial process to approve or deny the application.

• Restricting the placement or location of an ADU or JADU such that it would be rendered infeasible or unusable by the property owner.

• Requiring major structural elements or design changes beyond the requirements set forth in State ADU and JADU Law that would extinguish the ability to construct or use the ADU or JADU.

• Imposing restrictions that are not objective or not knowable or available to the property owners in advance of submitting the application.

• Levying excessive application fees, conditions, or other financial requirements that would cause the property owner to incur substantial costs or forgo the development, such as requiring owner-occupancy of an ADU or charging excessive maintenance fees that would be unreasonable considering the size of the ADU proportionally to the primary dwelling.

Property owners whose construction or use of an ADU or JADU is impeded by an HOA (or their representatives or agents) are encouraged to reach out to their local agency and to seek legal counsel.

Yes. Pursuant to Government Code sections 66330, and 65583.1, ADUs and JADUs may be utilized towards the RHNA and the Housing Element Annual Progress Report (APR) required by Government Code section 65400. To credit a unit toward the RHNA, HCD and the Department of Finance (DOF) utilize the U.S. Census definition of a housing unit. Generally, an ADU, and a JADU with shared sanitation facilities, and any other unit that meets the U.S. Census definition and is reported to DOF as part of the DOF annual City and County Housing Unit Change Survey can be credited toward the RHNA based on the appropriate income level. The housing element or APR must include a reasonable methodology to demonstrate the level of affordability. Local governments can track actual or anticipated affordability to assure ADUs and JADUs are counted towards the appropriate income category. For example, some local governments request and track information such as anticipated affordability as part of the building permit or other local applications.

For more information, please refer to the Housing Element Building Blocks or contact HousingElements@hcd.ca.gov.

To count ADUs towards the RHNA in the housing element, local agencies must generally use a three-part approach: (1) development trends, (2) anticipated affordability, and (3) resources and incentives. Development trends must consider ADUs permitted in the prior planning period and may also consider more recent trends. Anticipated affordability can use a variety of methods to estimate the affordability by income group. Common approaches include rent surveys of ADUs, using rent surveys and square footage assumptions and data available through the APR required by Government Code section 65400. Resources and incentives include policies and programs to encourage ADUs, such as prototype plans, fee waivers, expedited procedures, and affordability monitoring programs.

A “junior accessory dwelling unit” or JADU is a unit that is no more than 500 square feet in size and contained entirely within a single-family residence. A JADU may include separate sanitation facilities or may share sanitation facilities with the existing structure. (Gov. Code, § 66333.)

No. Only one JADU may be created per lot zoned for single-family residences with an existing or proposed single-family residence (Gov. Code, § 66333, subd. (a)). The JADU may be created within the walls of the proposed or existing single-family residence, including attached 29 garages (Gov. Code, § 66333, subd. (d)). If there are multiple detached single-family residential units on one lot, there can only be one JADU.

Yes. Pursuant to Government Code section 66310, the California Legislature found and declared that, among other things, California is facing a severe housing crisis and ADUs are a valuable form of housing that meets the needs of family members, students, the elderly, inhome health care providers, people with disabilities, and others. Therefore, ADUs are an essential component of California’s housing supply.

Recent changes to State ADU Law intend to address barriers, streamline approval, and expand potential capacity for ADUs, recognizing their unique importance in addressing California’s housing needs. The preparation, adoption, amendment, and implementation of local ADU ordinances must be carried out consistently with Government Code section 66310 and must not unduly restrict the creation of ADUs. Local governments adopting ADU ordinances should carefully weigh the adoption of zoning, development standards, and other provisions for impacts on the development of ADUs.

State ADU Law provides the statutory minimum requirements for ADUs and JADUs. Local governments may elect to go beyond this statutory minimum to further the creation of ADUs. (Gov. Code, § 66325, subd. (b).) Many local governments have embraced the importance of ADUs as an important part of their overall housing policies and have pursued innovative strategies.

Yes. One common strategy used by local agencies to promote ADU development is to adopt ADU bonus programs. HCD supports this approach to go above and beyond State ADU Law’s requirements to address California’s ongoing housing crisis. A successful ADU bonus program should meet the following criteria:

1. The ADU bonus program is completely optional – There is no requirement, and no consequence for not taking part in a local bonus program.

2. The ADU bonus program only offers benefits in addition to the provisions of State ADU Law, not in lieu of them – All state-mandated requirements are granted unconditionally.

3. The ADU bonus program removes one or more physical constraints, such as a limitation on the number of allowable units on a lot, ADU size, height, setback requirements, or a waiver of design and development criteria.

No. A lot, as defined in Health and Safety Code sections 18210 and 18862.23, allows for only one manufactured home, mobilehome, or recreational vehicle. Health and Safety Code section 18862.23 also allows one tent, camp car, camping cabin, or camping party on a lot within a special occupancy park.

For more information, please contact the Division of Codes and Standards at: NAOStaff@hcd.ca.gov for Northern CA or SAOStaff@hcd.ca.gov for Southern CA.

For the purposes of creating an ADU, a structure with two or more attached dwellings on a single lot is considered a multifamily dwelling structure. Multiple detached single-unit dwellings on the same lot are not considered multifamily dwellings for the purposes of State ADU Law.

Yes. A local agency must permit an attached, detached, or converted ADU on a lot that is zoned to allow single-family or multifamily residential use and includes an existing or proposed dwelling (Gov. Code, § 66314, subds. (d)(2), (d)(3)). An applicant may build a detached or a converted ADU on a site in a residential or mixed-use zone with a proposed or existing multifamily dwelling. (Gov. Code, § 66323, subds. (a)(3), (a)(4).) (See next question for more information.)

No. State ADU Law limits a local agency’s ability to deny a permit application due to the correction of existing, nonconforming zoning conditions. Nonconforming zoning conditions are physical improvements on a property that do not conform to current zoning standards.

For 66323 Units, a local agency cannot condition approval on the correction of nonconforming zoning conditions. For all other ADUs, a local agency may only deny a permit to create an ADU due to zoning non-conformance when the non-conformance creates a threat to public health and safety and is affected by the construction of the ADU.

No. A local agency cannot impose an owner-occupancy requirement on any ADU.

No. Parking requirements for ADUs shall not exceed one parking space per unit or bedroom, whichever is less. These spaces may be provided as tandem parking on a driveway.

Guest parking spaces shall not be required for ADUs under any circumstances. In addition, a local agency may not require off-street parking spaces to be replaced when a garage, carport, covered parking structure, or uncovered parking space is demolished in conjunction with the construction of an ADU or converted to an ADU.

Local agencies may choose to eliminate or reduce parking requirements for ADUs, such as requiring zero or a fraction of a parking space per each ADU (such as a ½ space per unit), to further reduce barriers to ADU construction and to facilitate more development of mixed-modal transportation such as walking and public transit.

Yes. A local agency shall not impose parking standards on any of the following ADUs, pursuant to Government Code section 66322, subdivision (a):

1) ADUs located within one-half mile walking distance of public transit.

2) ADUs located within an architecturally and historically significant historic district.

3) ADUs that are part of the proposed or existing primary residence or an accessory structure.

4) When on-street parking permits are required but not offered to the occupant of the ADU.

5) When there is a car share vehicle located within one block of the ADU.

6) When a permit application for an ADU is submitted with a permit application to create a new single-family dwelling or a new multifamily dwelling on the same lot, provided that the ADU or the parcel satisfies any other criteria listed in Government Code section 66322, subdivision (a)(1)-(5).

Parking requirements for ADUs may not exceed one parking space per ADU or per bedroom, whichever is less. ADUs which have no bedrooms because they are an “efficiency unit” or studio do not increase the bedroom count.

In addition, local agencies may not impose parking requirements on 66323 Units.

A permitting agency is “any entity that is involved in the review of a permit for an accessory dwelling unit or JADU and for which there is no substitute, including, but not limited to, applicable planning departments, building departments, utilities, and special districts.”

Yes. ADUs subject to State ADU Law must be considered, approved or denied, and permitted ministerially, without discretionary review or a hearing. Development standards must be objective to allow for ministerial review. Objective standards require a uniform benchmark or reference that is knowable by both the permit applicant and the permitting agency prior to the submission of an application to create or serve an ADU.

Yes. Local agencies may require that ADUs be used for rentals of terms longer than 30 days. ADUs created pursuant to Government Code section 66323 must be rented for terms longer than 30 days.

A local agency may adopt a local ordinance to allow separate conveyance of the primary unit and the ADU as condominiums if the ordinance meets specific requirements laid out in Government Code section 66342. In addition, Government Code section 66341 creates a narrow exception to allow separate conveyance of an ADU to a qualified buyer if the property was built or developed by a qualified nonprofit corporation and meets other requirements specified in section 66341.

SB 9 and State ADU Law are complementary. Both laws can be implemented in ways that result in developments with both “SB 9 Units” and ADUs. However, in no case does SB 9 require a local agency to allow more than four units on a single lot, in any combination of primary units and ADUs or JADUs. For example, when a lot split has not occurred, the lot is eligible to receive a second primary unit on the lot under SB 9 and to receive up to two ADUs under State ADU Law.

When a lot split occurs under SB 9, each lot is eligible for up to two units, including, for example, a primary unit and an ADU or JADU. In the case that a lot owner both splits a lot and builds two primary units on each resulting lot under SB 9, State ADU Law is superseded (i.e., neither lot is entitled to an ADU or JADU); in all other cases, State ADU Law applies, up to SB 9’s four-unit cap.

Members of the public with SB 9 complaints are encouraged to share them to the Housing Accountability Unit Portal.

Yes. A local agency may impose objective development standards, such as setbacks, for the creation of ADUs. A setback of no more than four feet from the side and rear lot lines shall be required for an attached or detached ADU. Additional setback requirements may be required in the Coastal Zone if required by a local Coastal Program.

No setback shall be required for an ADU or JADU created within an existing living area or accessory structure or an ADU created in a new structure in the same location and to the same dimensions as an existing structure.

The CBC provides the minimum standards to which all buildings in California must be built (California Building Code, Vol. 2, 1.1.3). The CBC also allows local agencies to adopt amendments, additions, or deletions to the provisions of the CBC which are reasonably necessary and are more restrictive than the CBC’s standards (California Building Code, Vol. 2, 1.1.8).

The CBC defines “Floor Area, Gross” as “[t]he floor area within the inside perimeter of the exterior walls of the building under consideration, exclusive of vent shafts and courts, without deduction for corridors, stairways, ramps, closets, the thickness of interior walls, columns or other features. The floor area of a building, or portion thereof, not provided with surrounding exterior walls shall be the usable area under the horizontal projection of the roof or floor above. The gross floor area shall not include shafts with no openings or interior courts.”

Government Code section 66314, subdivision (d)(8) states that a local ADU ordinance must require ADUs to comply with local building codes. Thus, when a local agency has not adopted specific changes to the CBC in its local building standards, then the CBC standards, and in this case the definition of floor area, shall apply. If the local agency has made specific amendments, additions, or deletions relating to the definition of “Floor Area” within its local building standards, then those altered definitions shall apply.

No. Local governments may not include minimum lot size requirements for ADUs.

Yes, newly constructed ADUs are subject to the California Energy Code requirement (excluding manufactured homes) to provide solar systems if the unit(s) is a newly constructed, detached ADU (though some exceptions apply). Per the California Energy Commission (CEC), the solar systems can be installed on the ADU or on the primary dwelling unit. ADUs that are constructed within existing space, or as an addition to existing homes, including detached additions where an existing detached building is converted from non-residential to residential space, are not subject to the California Energy Code requirement to provide solar systems.

Please refer to the CEC on this matter. For more information, see the CEC’s website at www.energy.ca.gov. You may email your questions to title24@energy.ca.gov, or contact the Energy Standards Hotline at 800-772-3300. CEC memos can also be found on HCD’s website at https://www.hcd.ca.gov/policy-and-research/accessory-dwelling-units.

.

Possibly. While State ADU Law does not specifically reference “tiny homes,” “tiny home” is an industry term that can mean different structures or vehicles. If the unit meets the definition of an ADU in Government Code section 66313, subdivision (a), it is subject to ADU Law.

For more information on “tiny homes,” see Information Bulletin 2016-01 at https://www.hcd.ca.gov/policy-research/docs/hcd-bulletin-tiny-home-ib-2016-01.pdf. ContactMH-FBH@hcd.ca.gov. You may also contact HCD’s Division of Codes and Standards at ContactMH-FBH@hcd.ca.gov.

An attached ADU is a newly created (constructed) dwelling structure that structurally abuts (and connects to) an existing or proposed primary dwelling or accessory structure. This can be constructed on top of or below the primary dwelling. The attached ADU extends beyond the building plane of the existing or proposed primary dwelling unit. An attached ADU shall not exceed 50 percent of the existing primary dwelling’s floor area size.

Examples of attached ADUs include, but are not limited to:

• An ADU addition to a duplex.

• An ADU built on top of an attached garage.

• An ADU built as a new second story of a single-family dwelling.

• An ADU built in a newly constructed basement.

Converted ADUs are dwelling units that are created from existing space within proposed or existing primary dwelling units or existing accessory structures. For single family residences, the converted ADU is created from the proposed or existing space of the single-family residence or the existing space of an accessory structure. For multifamily dwelling structures, the converted ADUs are created from portions of the multifamily dwelling structures that are not used as livable space (i.e., storage rooms, passageways, etc.).

Local agencies may not deny a permit for an unpermitted ADU or JADU created prior to January 1, 2020. An inspector from the local agency may inspect the unit for compliance with health and safety standards and provide recommendations to comply with health and safety standards necessary to obtain a permit. If the inspector finds noncompliance with health and safety standards, the local agency shall not penalize an applicant for having the unpermitted ADU or JADU and shall approve necessary permits to correct noncompliance with health and safety standards. However, the local agency may deny a permit if it finds that the building is substandard. This does not preclude the local agency from pursuing enforcement action on these violations, and an applicant may be required to make alterations or repairs accordingly.

A local agency shall inform the public about the provisions of this section through public information resources, including permit checklists and the local agency’s internet website, which shall include both of the following: (1) a checklist of the conditions specified in Section 17920.3 of the Health and Safety Code that would deem a building substandard, and (2) information that, before applying for a permit, the homeowner may obtain a confidential third-party code inspection from a licensed contractor to determine the unit’s existing condition or potential scope of building improvements.

See the Department of Consumer Affairs’ Contractors State License Board’s contractor license check resource, available at https://www2.cslb.ca.gov/onlineservices/checklicenseII/checklicense.aspx.

ADUs and JADUs created from the existing space of a primary dwelling or accessory structure pursuant to Government Code section 66323, subdivision (a)(1), cannot be required to install a new or separate connection unless the ADU is constructed concurrently with a new single-family dwelling. For all other ADUs not created pursuant to Government Code section 66323, subdivision (a)(1), a new or separate connection directly from the utility to the ADU may be required.

HCD does not have authority over issues related to gas and electrical services. If an applicant believes that a local utility provider is not complying with connection requirements, fee schedules, or other issues that impact the creation of or service of an ADU, the applicant can file a complaint with the appropriate agency.

For privately owned public utilities such as PG&E, contact the California Public Utilities Commission (CPUC) by using CPUC’s online complaint form, by calling 1-800-649-7570, or by sending a letter to:

California Public Utilities Commission

505 Van Ness Avenue

San Francisco, CA 94102–3298

For publicly owned utilities such as SMUD, the applicant will need to contact the utility directly and follow their complaint process.

No. Local agencies may, by ordinance, designate where ADUs are permitted within zones that allow residential use. However, any limits on where ADUs are allowed may only be based on the adequacy of water and sewer service and on the impacts on traffic flow and public safety.

Local governments may not preclude the creation of ADUs altogether, and any limitation should be accompanied by detailed findings of fact explaining why ADU limitations are required and consistent with these factors. If a lot with a residence has been rezoned to a use that does not allow for residential uses, that lot is no longer eligible for an ADU. Impacts on traffic flow should consider factors like lower car ownership rates for ADUs. Finally, local governments may develop alternative procedures, standards, or special conditions with mitigations for allowing ADUs in areas with potential health and safety concerns.

HCD understands that extreme weather conditions occur, and the threat of destructive wildfires cannot be ignored. Some agencies have used the High (HFHSZ) and Very High Fire Hazard Severity Zone (VHFHSZ) maps provided by CAL FIRE to mark areas where ADUs may be restricted or prohibited altogether. However, according to CAL FIRE, the HFHSZ and VHFHSZ maps are intended to govern building materials used in construction and defining zones of defensibility around structures. These are not intended to restrict housing development. The presence of a High Fire Hazard Severity Zone is not a conclusive rationale to warrant restricting ADUs. A restriction based on the threat to public safety should be supported with findings detailing the impact of ADUs on public safety.

Detached ADUs are newly constructed dwelling units that are created on a lot with an existing or proposed single-family or multifamily dwelling structure but are detached from the primary dwelling.

Yes. Multifamily lots qualify for two detached, new construction ADUs on lots with a proposed multifamily dwelling, or up to eight detached ADUs on a lot with an existing multifamily dwelling, not to exceed the total number of existing units on the lot. These ADUs are detached from the primary multifamily structure but do not have to be detached from each other or other accessory structures on the lot.

An ADU is accessory to a primary residence and has complete independent living facilities for one or more persons. ADUs are either “detached from,” “attached to,” or located within the proposed or existing primary dwelling. This includes attached garages, storage areas or similar spaces, and accessory structures. The ADU can also be detached from the proposed or existing primary dwelling, including detached garages, provided it is located on the same lot. (Gov. Code. §§ 66313, subd. (a); 66314, subd. (d)(3).)

Note that certain federal financing programs mentioned in the section on “Funding,” below, may have different definitions of an ADU.