Hawthorne Municipal Code Ch. 17 24b. ACCESSORY DWELLING

§ 17.24b.010. Purpose.

The purpose of this chapter is to establish regulations for the development of accessory dwelling units (ADU) and junior accessory dwelling units (JADU) as defined in this chapter and in California Government Code § 66310 et seq., or any successor statute.

(Ord. 2265, 7/14/2026[1])

[1]

Editor's Note: This chapter was renumbered from Ch. 17.21.

§ 17.24b.020. Permit requirement.

A. Planning Approval. Planning approval is required for construction of an accessory dwelling unit (ADU) or junior accessory dwelling unit (JADU) or the modification of exterior features, size, or height of an existing ADU or JADU.

B. Building Permit. A building permit shall be required for construction or modification of an ADU or JADU as set forth in the California Residential Code and other building standards adopted by the City. The building permit may require approval by multiple agencies, including the Directors of the Building Safety Department and the Planning Department.

(Ord. 2265, 7/14/2026)

§ 17.24b.030. Permit application and review procedures.

A. The Director, or designee, shall review and approve or deny ministerial permits for ADUs and JADUs upon determining whether the application submitted is complete, the proposed unit conforms to all requirements of this Code and state law, and a non-refundable application review fee in the amount established by the City Council, amended from time to time, has been paid. Applications deemed incomplete or not in full conformance with the requirements of this Code will be rejected. The Director will review the application without public notice or hearing. The time period for review may be tolled at the request of the applicant.

B. Decision. The Director shall render a decision in writing. If the Director denies an application, they shall return a full set of comments to the applicant with a list of items that are defective or deficient and a description of how the application can be remedied by the applicant.

C. Time Limit. The Director shall approve or deny an application for an ADU or JADU within 60 days after receiving the application. Applications shall be considered approved if not acted upon within 60 days after receiving the application.

D. Pre-Approved ADUs. The City has preapproved ADU plans for new ADUs for use by Hawthorne residents. The preapproved ADUs are available at the Planning Department.

(Ord. 2265, 7/14/2026)

§ 17.24b.040. Zoning and applicability.

A. An ADU or JADU is permitted in any General Plan Land Use designation that allows residential uses by-right.

B. Site with Existing Single-Family Residence. Sites with the appropriate land use designation and developed or proposed to be developed with a single-family residence shall be permitted not more than one attached ADU, one detached ADU, and one JADU.

C. Site with Existing Multifamily Residence.

Sites with existing multifamily structures may convert existing non-habitable areas within the building to a minimum one ADU and a maximum that shall not exceed 25% of the number of permitted units on the site.
Sites with existing multifamily structures are permitted to construct or convert not more than eight detached accessory dwelling units. However, the number of accessory dwelling units allowable pursuant to this clause shall not exceed the number of existing units on the lot.
Sites with a proposed multifamily structure may construct two detached accessory dwelling units.

(Ord. 2265, 7/14/2026)

§ 17.24b.050. Development standards.

A. Minimum Size. The minimum size for an ADU or JADU is 190 square feet.

B. Maximum Size.

Attached ADU or within an existing primary dwelling unit. Not to exceed 50% of the area of the existing primary dwelling unit, but at least 800 square feet of interior livable space.
Detached ADU. Not to exceed 1,000 square feet of interior livable space.
Conversion of existing detached structure to ADU. Same as existing structure.
JADU. 500 square feet.

C. Maximum Height.

Detached ADU, generally: 16 feet and one story.
Detached ADU within 0.5 miles of a major transit stop or high-quality transit corridor, as those terms are defined in Public Resources Code § 21155: 20 feet and two stories.
Detached ADU on a lot with an existing or proposed multi-story multifamily structure: 20 feet and two stories.
Attached ADU: same as the height limit of the existing or proposed single-family structure, not to exceed 25 feet.

D. Minimum Side and Rear Setbacks.

Conversion of an existing structure: an ADU may be built within an existing structure or within the footprint of the structure without regard to setbacks.
New attached or detached ADU: four feet.
ADUs or JADUs within an existing or proposed primary dwelling unit shall follow the setback applicable to the primary dwelling unit in as prescribed by the zone it which is located.

E. Maximum Lot Coverage. The lot coverage of the zone shall apply, except that an ADU of at least 800 square feet shall be permitted to exceed the lot coverage if developed in compliance with all other applicable development standards.

F. Open Space. For a detached or attached ADU: 500 square feet, except that an ADU of at least 800 square feet shall be permitted without meeting this standard if developed in compliance with all other applicable development standards.

G. Minimum Parking Spaces per ADU. One, except no additional parking shall be required in the following instances:

The ADU is located within 0.5 miles of public transit;
The ADU is located within an architecturally and historically significant historic district;
The ADU is a conversion of an existing accessory structure (such as a garage, carport, or workshop) or within the primary dwelling unit;
The ADU is located in an area where on-street parking permits are required but not offered to the ADU occupant; or
The ADU is located within one block of a car share vehicle.

Parking requirements may be satisfied by tandem parking on a driveway.

H. Expansion of Existing Structures. Existing structures converted into an ADU or JADU may be expanded by up to 150 square feet only to accommodate an entryway.

I. Building Separation. The building separation requirement may be reduced to permit an ADU up to 800 square feet in size. Separation shall be measured from the nearest points between the structures. This provision shall not apply to conversions of existing buildings.

(Ord. 2265, 7/14/2026)

§ 17.24b.060. Additional ADU and JADU requirements.

A. Illegal Units. Any combination of rooms, so arranged that they can be converted into separate living quarters, may, at the discretion of the Director, be counted as additional dwelling units or ADUs.

B. Fire Sprinklers. Fire sprinklers are required in an ADU if sprinklers are required in the primary residence.

C. Nonconforming Zoning Conditions. No corrections to nonconforming zoning conditions that do not present a threat to public health and safety are required for the creation or conversion of an ADU or JADU.

D. Utility Connections. For accessory dwelling units described in California Government Code § 66323(a)(1), the ADU or JADU shall not be required to install a new or separate utility connection directly between the ADU or JADU and the utility, and the ADU or JADU shall not be subject to a related connection fee or capacity charge, unless the ADU is constructed concurrently with a new single-family home.

E. Rental Term. ADUs and JADUs may be rented but shall not be used as rentals for a term less than 30 consecutive days.

F. Historic properties. ADUs and JADUs shall conform to the United States Secretary of Interior's Official Standards for the Treatment of Historic Properties.

§ 17.24b.070. Deed restriction for JADU.

Prior to the issuance of a building permit for a JADU that will use shared sanitation facilities with the existing structure, a deed restriction must be recorded against the title of the property in the County Recorder's office and a copy filed with the Director. The deed restriction shall run with the land and bind all future owners. The form of the deed restriction will be provided by the City and must provide that:

A. The JADU shall not be sold separately from the primary dwelling.

B. The unit is restricted to the approved size and attributes of this chapter.

C. The covenant restrictions run with the land and may be enforced against future purchasers.

D. The covenant restrictions may be removed if the owner eliminates the JADU, as evidenced by, for example, removal of the kitchen facilities. To remove the deed restriction, an owner may make a written request of the Director, providing evidence that the JADU has in fact been eliminated. Any building permits required in the removal must be approved prior to the Director's determination. The Director may then determine whether the evidence supports the claim that the JADU was eliminated. Appeal may be taken from the Director's determination consistent with other provisions of this Code. If the JADU is not entirely physically removed but is only eliminated by virtue of having a necessary component of a JADU removed, the remaining structure and improvements must otherwise comply with applicable provisions of this Code.

E. The deed restriction is enforceable by the Director or designee for the benefit of the City. Failure of the property owner to comply with the deed restriction may result in legal action against the property owner, and the City is authorized to obtain any remedy available to it at law or equity, including, but not limited to, obtaining an injunction enjoining the use of the JADU in violation of the recorded restrictions or abatement of the illegal unit.