§ 155.316 ACCESSORY DWELLING UNITS. — Eureka Zoning Code

§ 155.316.010 PURPOSE. ¶

This section establishes standards for accessory dwelling units and junior accessory dwelling units in conformance with Cal. Government Code §§ 66310 - 66324. See § 155.304.130 (Tiny Houses on Wheels) for regulations to use a tiny house on wheels as an accessory dwelling unit.

(Ord. 885-C.S., passed 5-21-19; Am. Ord. 902 C.-S., passed 8-18-20; Am. Ord. 938-C.S., passed 11-1-22; Am. Ord. 951-C.S., passed 10-17-23; Am. Ord. 965-C.S., passed 8-19-25)

§ 155.316.020 PERMITTING PROCESS. ¶

(A) Zoning clearance. Accessory dwelling units and junior accessory dwelling units consistent with the requirements of this section are allowed by-right with a zoning clearance (i.e., building permit approval).

(B) Time limit to act.

(1) On lots with an existing single- or multi-family dwelling, an accessory dwelling unit or junior accessory dwelling unit shall be approved or denied within 45 days of submission of a complete application.

(2) If an applicant applies for both a new primary dwelling and an accessory dwelling unit or junior accessory dwelling unit, the city may delay approving or denying the accessory dwelling unit or junior accessory dwelling unit the city approves or denies the primary dwelling.

(Ord. 885-C.S., passed 5-21-19; Am. Ord. 951-C.S., passed 10-17-23; Am. Ord. 965-C.S., passed 8-19-25)

§ 155.316.030 WHERE ALLOWED. ¶

An accessory dwelling unit is permitted on any lot where single- or multi-family dwellings are a permitted use, and where there is an existing or proposed primary dwelling.

(Ord. 885-C.S., passed 5-21-19; Am. Ord. 902 C.-S., passed 8-18-20; Am. Ord. 951-C.S., passed 10-17-23; Am. Ord. 965-C.S., passed 8-19-25)

§ 155.316.040 NUMBER OF ACCESSORY DWELLING UNITS. ¶

(A) Single family dwelling.

(1) On a lot with an existing or proposed single-family dwelling, the following maximum number of accessory dwelling units are allowed:

(a) Two attached or detached accessory dwelling units; and
(b) One junior accessory dwelling unit pursuant to Cal. Government Code §§ 66333 - 66339.
(2) Relationship to SB 9 residential developments and urban lot split subdivisions in the RE and R1 Zoning Districts.
(a) In no case shall the total number of primary dwellings, accessory dwelling units, and junior accessory dwelling units exceed four on any given lot in the RE or R1 Zoning Districts.
(b) When a lot split occurs under Cal. Government Code § 66411.7 and § 155.332.030 (Urban Lot Split Subdivisions), each

resulting lot is limited to three dwelling units: one single-family home, one junior accessory dwelling unit, and either one additional single-family home or one accessory dwelling unit.

(B) Multi-family dwelling.

(1) On a lot with an existing multi-family dwelling, the following maximum number of accessory dwelling units are allowed:

(a) Up to eight detached accessory dwelling units, provided the number of accessory dwelling units does not exceed the number of existing primary dwelling units on the lot (detached accessory dwelling units are not required to be detached from each other but must be detached from the multi-family dwelling); and

(b) One or more accessory dwelling units within portions of the existing multi-family dwelling that are not used as liveable space. Examples of such areas include garages, storage rooms, boiler rooms, passageways, attics, and basements that are not used as habitable space. The number of these internal accessory dwelling units may not exceed 25% of the total number of dwelling units in the existing structure, or at least one accessory dwelling unit, whichever is greater.

(2) On a lot with a proposed multi-family dwelling, not more than two attached or detached accessory dwelling units are allowed.

(Ord. 885-C.S., passed 5-21-19; Am. Ord. 902 C.-S., passed 8-18-20; Am. Ord. 951-C.S., passed 10-17-23; Am. Ord. 965-C.S., passed 8-19-25)

§ 155.316.050 ACCESSORY DWELLING UNITS AS SHORT-TERM RENTALS. ¶

An accessory dwelling unit or junior accessory dwelling unit in a residential or mixed-use zoning district may not be converted to, or utilized as, a short-term, transient, vacation rental or commercial lodging if the accessory dwelling unit or junior accessory dwelling unit was granted a certificate of occupancy after January 1, 2020.

(Ord. 885-C.S., passed 5-21-19; Am. Ord. 902 C.-S., passed 8-18-20; Am. Ord. 931-C.S., passed 2-15-22; Am. Ord. 951-C.S., passed 10-17-23; Am. Ord. 965-C.S., passed 8-19-25)

§ 155.316.060 SITE AND DESIGN STANDARDS. ¶

(A) General standards.

(1) Accessory dwelling units and junior accessory dwelling units are not considered for the purposes of evaluating the density requirements established by the general plan; are considered residential uses; and may count as a dwelling unit for purposes of identifying adequate sites for housing.

(2) Accessory dwelling units may be sold separately from the primary dwelling unit(s) only as permitted by Cal. Government Code §§ 66341 or 66342.

(3) Accessory dwelling units and junior accessory dwelling units must comply with the state building standards for dwellings as determined by the Building Official, except as provided by division (I)(2) below.

(4) The floor area of an accessory dwelling unit or junior accessory dwelling unit may not be less than the floor area required for an efficiency dwelling unit.

(B) Height, FAR, and site coverage.

(1) Accessory dwelling units are subject to the same height standards that apply to primary dwellings on the lot in the applicable zoning district.

(2) FAR and site coverage standards do not apply to accessory dwelling units.

(C) Relationship to residential structures.

(1) An accessory dwelling unit may be within, attached to, or detached from a single- or multi-family residential structure.

(2) A junior accessory dwelling unit must be contained entirely within an existing or proposed single-family residence. For purposes of this standard, enclosed uses within the residence, such as attached garages, are considered a part of the residence.

(3) An accessory dwelling unit or junior accessory dwelling unit within a proposed or existing primary residence must have its own separate exterior access.

(4) An accessory dwelling unit or junior accessory dwelling unit must have kitchen and bathroom facilities that are separate from the primary dwelling, except as allowed by division (C)(5) below.

(5) A junior accessory dwelling unit may have an efficiency kitchen as defined in Cal. Government Code § 66333(f). Bathroom facilities, but not the efficiency kitchen, may be shared with the primary dwelling. If the bathroom is shared with the primary dwelling, the junior accessory dwelling unit must have an interior entry to the primary dwelling's main living area. (D) Maximum unit size.
(1) Junior accessory dwelling unit. The floor area of a junior accessory dwelling unit may not exceed 500 square feet in size. See § 155.112.050(B) (Floor Area Calculation for Junior Accessory Dwelling Unit) for rules of measurement.
(2) Accessory dwelling unit.
(a) The floor area for an accessory dwelling unit (either attached or detached) may not exceed 1,200 square feet.
(b) Accessory dwelling units that qualify for approval under Cal. Government Code § 66323(a)(1), (3), or (4) are exempt from this maximum size requirement.
(3) Calculating size. The floor area calculation for accessory dwelling units and junior accessory dwelling units does not include covered parking.

(E) Existing home designated as accessory unit. If a lot contains an existing single-family home 1,200 square feet in size or smaller, the existing home may be designated as an accessory dwelling unit as part of a project to construct a new single-family home on the lot.

(F) Setbacks; minimum setbacks from property lines. The setbacks for accessory dwelling units shall be the same as those required for primary structures in the applicable zoning district, except as provided below:
(1) Side and rear setbacks. The minimum side and rear setback for accessory dwelling units is four feet, unless the applicable zoning district permits a smaller minimum setback for primary structures, in which case that smaller setback applies.
(2) Second floor or conversion. No additional setbacks are required for:
(a) An existing structure that is converted to an accessory dwelling unit;
(b) An accessory dwelling unit constructed above an existing structure; or
(c) An accessory dwelling unit constructed in the same location as an existing structure, provided any modifications to the dimensions do not expand the footprint in the nonconforming setback area.
(3) Front setback exemption. No minimum front setback is required for:
(a) A new-construction accessory dwelling unit that is 800 square feet or smaller in floor area and complies with minimum four-foot side and rear yard setbacks.
(b) Accessory dwelling units and junior accessory dwelling units that qualify for approval under Cal. Government Code § 66323(a)(1) - (4).
(G) Parking.
(1) On-site parking is not required for accessory dwelling units or junior accessory dwelling units.
(2) When an existing parking space (covered or uncovered) is eliminated in conjunction with the creation of an accessory dwelling unit or junior accessory dwelling unit, replacement parking is not required for the eliminated parking space.
(H) Historic review. New construction, exterior alterations or additions for an accessory dwelling unit on a property listed on the Local Register of Historic Places shall comply with Eureka Municipal Code Chapter 157, except the following types of accessory dwelling units are exempt from Historic Preservation Review:
(1) A new-construction, detached accessory dwelling unit not located between a historic building and the street.
(2) The conversion of an existing interior space or structure to an accessory dwelling unit where no exterior alterations are proposed (interior construction only).
(3) A new-construction attached accessory dwelling unit that is not visible from the sidewalk, alley or street because it is blocked from view by permanent structures.
(4) Accessory dwelling units that qualify for approval under Cal. Government Code § 66323(a)(1) - (4).
(I) Nonconformities.
(1) New construction, exterior alterations or additions for an accessory dwelling unit or junior accessory dwelling unit are not subject to § 155.424.030(B) (Required Compliance), and do not trigger the need to correct nonconforming zoning conditions,

building code violations, or unpermitted structures that do no present a threat to public health and safety and are not affected by the creation of the accessory dwelling unit or junior accessory dwelling unit.

(2) An application for an unpermitted accessory dwelling unit or junior accessory dwelling unit constructed before January 1, 2020 that violates building or zoning standards shall be approved unless the Building Official finds that correcting the violation is necessary to protect the health and safety because the building is substandard pursuant to Cal. Health and Safety Code § 17920.3.

(J) Additional junior accessory dwelling unit requirements.

(1) The owner of the property must reside in either the remaining portion of the single-family residence or the junior accessory dwelling unit, except if the owner is a governmental agency, land trust or housing organization.

(2) A deed restriction must be filed including:

(a) A prohibition on the sale of the junior accessory dwelling unit separate from the sale of the single-family residence; and

(b) A restriction on the size and attributes of the junior accessory dwelling unit in conformance with Government Code §§ 66333 - 66339.

(Ord. 902 C.-S., passed 8-18-20; Am. Ord. 916-C.S., passed 7-6-21; Am. Ord. 951-C.S., passed 10-17-23; Am. Ord. 965-C.S., passed 8-19-25)

§ 155.316.070 INTERPRETATION. ¶

Any ambiguities in this section shall be interpreted to be consistent with state law.

(Ord. 951-C.S., passed 10-17-23; Am. Ord. 965-C.S., passed 8-19-25)