§ 13-36. Two-unit housing development. — Costa Mesa Zoning Code

(a) For purposes of this section, the following definition shall apply:
1. "Housing development" shall mean no more than two primary residential units within a single-family zone that meets the requirements of this section. The total number of units, including ADUs and JADUs, shall not exceed four.
(b) The city shall ministerially approve a housing development containing no more than two residential units if it meets the following requirements:
1. The parcel is located within a single-family residential zone.
2. The parcel is located at least partially in an urbanized area or urban cluster as designated by the United States Census Bureau.
3. The parcel is not located in any of the following areas and does not fall within any of the following categories:
  - a. A historic district or property included on the State Historic Resources Inventory, as defined in section 5020.1 of the Public Resources Code, or within a site that is designated or listed as a city landmark or historic property or district pursuant to a city ordinance.
  - b. Prime farmland or farmland of statewide importance as further defined in Government Code section 65913.4(a)(6)(B) .
  - c. Wetlands as defined in the Unites States Fish and Wildlife Service Manual, Part 660 FW 2 (June 21, 1993).
  - d. A hazardous waste site that is listed pursuant to section 65962.5 or a hazardous waste site designated by the Department of Toxic Substances Control pursuant to section 25356 of the Health and Safety Code, unless the State Department of Public Health, State Water Resources Control Board, or Department of Toxic Substances Control has cleared the site for residential use or residential mixed uses.
  - e. A delineated earthquake fault zone as determined by the State Geologist in any official maps published by the State Geologist, unless the development complies with applicable seismic protection building code standards adopted by the California Building Standards Commission under the California Building Standards Law and by the city's building department.
  - f. A special flood hazard area subject to inundation by the one percent annual chance flood (100-year flood) as determined by the Federal Emergency Management Agency (FEMA) in any official maps published by FEMA. If an applicant is able to satisfy all applicable federal qualifying criteria in order to provide that the site satisfies this subparagraph and is otherwise eligible for streamlined approval under this section, the city shall not deny the application on the basis that the applicant did not comply with any additional permit requirement, standard, or action adopted by the city that is applicable to that site. A development may be located on a site described in this subparagraph if either of the following are met:
    - i. The site has been subject to a Letter of Map Revision prepared by FEMA and issued to the city; or

ii. The site meets FEMA requirements necessary to meet minimum flood plain management criteria of the Nation Flood Insurance Program as further spelled out in Government Code section 65913.4(a)(6)(G)(ii) ;

- g. A regulatory floodway as determined by FEMA in any of its official maps, published by FEMA unless the development has received a no-rise certification in accordance with 44 C.F.R. § **60.3(d)(3)** . If an applicant is able to satisfy all applicable federal qualifying criteria in order to provide that the site satisfies this subparagraph and is otherwise eligible for streamlined approval under this section, the city shall not deny the application on the basis that the applicant did not comply with any additional permit requirement, standard, or action adopted by the city that is applicable to that site. 

- h. Lands identified for conservation in an adopted natural community conservation plan, habitat conservation plan, or other adopted natural resource protection plan as further spelled out in Government Code section **65913.4(a)(6)(l)** . 

- i. Habitat for protected species identified as candidate, sensitive, or species of special status by state or federal agencies, fully protected species, or species protected by the federal Endangered Species Act of 1973 (16 U.S.C. Sec. **1531** et seq.), the California Endangered Species Act (Chapter 1.5 (commencing with section **2050** ) of Division 3 of the Fish and Game Code), or the Native Plant Protection Act (Chapter 10 (commencing with section **1900** ) of Division 2 of the Fish and Game Code). 

- j. Lands under a conservation easement.

The proposed housing development would not require demolition or alteration of any of the following types of housing:
- a. Housing that is subject to a recorded covenant, ordinance or law that restricts rents to levels affordable to persons and families of moderate, low, or very low income;
- b. Housing that is subject to any form of rent or price control by the city;
- c. A parcel or parcels on which an owner of residential real property exercised rights under Government Code section 7060 et seq. to withdraw accommodations from rent or lease within 15 years before the date of the application; or
- d. Housing that has been occupied by a tenant in the last three years.
Demolition of an existing unit shall not exceed more than 25% of the existing exterior structural walls unless the site has not been occupied by a tenant in the last three years.

(c) Standards and requirements. Except where superseded by the following provisions, two-unit housing development pursuant to Government Code section 65852.21 shall comply with development standards applicable to the R1 Single-Family Residential District including, but not limited to, Section 13-32 of this code:
1. No setback shall be required for an existing structure or a structure constructed in the same location and to the same dimensions as an existing structure.

Except for those circumstances described in subsection (c)(1) above, the setback for side and rear lot lines shall be four feet. The front setback shall be as set forth in the R-1 Single-Family Residential District standards.
1. The applicant shall provide easements for the provision of public services and facilities as required.
2. All lots shall have a minimum street frontage of 10 feet to provide for vehicular access, or 16-foot if the driveway serves two units. For a lot without physical street frontage, access to street frontage shall be provided by the granting of a duly recorded permanent easement for ingress and egress purposes in favor of the lot without physical street frontage.
3. In order to preserve the city's inventory of on-street parking, existing and proposed development pursuant to Government Code section 65852.21 shall be limited to one driveway ingress/egress per resultant lot.
4. Required off-street parking shall consist of at least one garage space per unit and the location and configuration of such parking shall be in compliance with the provisions of this code, except that no parking requirements shall be imposed in either of the following circumstances:
  - a. The parcel is located within one-half mile walking distance of either a high-quality transit corridor as defined by Public Resources Code section 21155(b) or a major transit stop as defined in Public Resources Code section 21064.3 ; or
  - b. There is a car share vehicle located within one block of the parcel.
5. For residential units connected to an on-site wastewater treatment system (septic tank), the applicant provides a percolation test completed within the last five years, or if the percolation test has been recertified, within the last 10 years, which shows that the system meets acceptable infiltration rates.

(d) The city shall not require or deny an application based on any of the following:
1. The city shall not impose any objective zoning, subdivision, or design review standards that would have the effect of physically precluding the construction of two units on either of the resulting parcels or that would result in a unit size of less than 800 square feet. If the city determines that the strict application of objective zoning, subdivisions or design standards would physically preclude the development of two units on a lot each with a minimum unit size of 800 square feet, the city may ministerially allow deviations from development standards generally applicable to the R-1 zoning district pursuant to city policies and/or regulations implementing this section if such deviation is in compliance with applicable building and fire code standards and regulations and if there are no other feasible means of complying with state law.
2. The city shall not deny an application solely because it proposes adjacent or connected structure provided that that all building code safety standards are met and they are sufficient to allow a separate conveyance.
(e) An applicant shall be required to sign an affidavit in a form approved by the city attorney to be recorded against the property stating the following:
1. That the uses shall be limited to residential uses.
2. That the rental of any unit created pursuant to this section shall be for a minimum of 31 days.
3. That the maximum number of units to be allowed on the parcels is two, including, but not limited to, units otherwise allowed pursuant to density bonus provisions, accessory dwelling units, junior accessory dwelling units, or units allowed pursuant to section 13-35 .
(f) The city may deny the housing development if the building official makes a written finding, based upon a preponderance of the evidence, that the proposed housing development project would have a specific, adverse impact, as defined and determined in Government Code section 65589.5(d)(2) , upon the public health and safety or the physical environment and for which there is no feasible method to satisfactorily mitigate or avoid the specific, adverse impact.
(g) The provisions of this section supersede any contrary provisions contained elsewhere in this code.
(Ord. No. 21-20, § 1, 12-7-21; Ord. 2025-07, 10/21/2025)