Antioch ADU / Granny Flat Ordinance

California Department of Housing and Community Development

Alexis Morris, Planning Manager

City of Antioch Revised Accessory Dwelling Unit Ordinance February 6, 2017

To Whom It May Concern,

Enclosed, please find a copy of the City of Antioch’s revised Accessory Dwelling Unit (ADU) ordinance adopted by the City Council on December 13, 2016. Please do not hesitate to contact me with any questions at 925-779-6141 or

Thank you.

Community De› e1o[im ant 19 e laartnaent




SECTION 1. Findinqs.

The Antioch City Council hereby finds, determines and declares as follows:

  1. The City of Antioch holds the right to make and enforce all laws and regulations not in conflict with general laws, and the City holds all rights and powers established by state law.

  1. On June 10, 2003, the City Council adopted Ordinance No. 1006-C-S regulating second residential units within the City of Antioch.

  1. On September 27, 2016, Governor Brown signed AB 2s99 (Bloom) and SB 1069 (Wieckowski) into law, amending Government Code section 65852.2 and mandating that all local agencies adopt an Accessory Dwelling Unit ordinance consistent with the new provisions by January 1, 2017.

  1. The Planning Commission conducted a duly noticed public hearing on November 16, 2016 at which time a resolution was approved to initiate and recommend to the City Council that this ordinance be adopted. The City Council held a duly noticed public hearing on December 13, 2016 at which time all interested persons were allowed to address the Council regarding adoption of this ordinance.

  1. The City Council finds that the public necessity requires the proposed zoning ordinance amendments to impose requirements for Accessory Dwelling Units within the City of Antioch that are consistent with State law; said amendments are not detrimental to properties within Antioch, and that the proposed zoning ordinance amendment is in conformance with the Antioch General Plan.

SECTION 2. Section 9-5.203 of the Antioch Municipal Code is hereby amended to modify the following definitions, with no other amendments to this Section:

DWELLING, SINGLE-FAMILY ATTACHED. A dwelling unit that is designed for occupancy by one household located on a separate lot from any other unit (except a secaed an accessory dwelling unit, where permitted), and attached through common vertical walls to one or more dwellings on abutting lots. Two attached single-unit dwellings may be configured as TOWNHOUSES or ROW HOUSES.

DWELLING, SINGLE•FAMILY DETACHED. A dwelling unit that is designed for occupancy by one household, located on a separate lot from any other dwelling unit (except a-secaed an accessory dwelling unit, where permitted), and not attached to

another dwelling unit on an abutting lot. This classification includes individual manufactured housing units installed on a foundation system pursuant to Cal. Health and Safety Code § 18551.

DWELLING, TWO-FAMILY OR DUPLEX. A single building on a separate lot that contains two dwelling units or two single-unit dwellings located on a single lot. This use is distinguished from a—secee8 an accessory dwelling unit, which is an accessory residential unit as defined by state law and this section.


. . . . . .

SECTION 3. Section 9-5.3805 is hereby rescinded and reenacted as follows: 9-5.3805 ACCESSORY DWELLING UNITS

  1. Definitions. For the purpose of this section, the following definitions shall apply unless the context clearly indicates or requires a different meaning.

ACCESSORY DWELLING UNIT. An attached or a detached residential dwelling unit which provides complete independent living facilities for one or more persons. It shall include permanent provisions for living, sleeping, eating, coOking, and sanitation on the same parcel as the single-family dwelling is situated. An accessory dwelling unit also includes the following: An efficiency unit, as defined in Section 17958.1 of Health and Safety Code; A manufactured home, as defined in Section 18007 of the Health and Safety Code.

ADMINISTRATIVE USE PERMIT. A land use permit defined in § 9-5.2701(E) of this Code, and issued by the Zoning Administrator or his/her designee without notice or public hearing.

JUNIOR ACCESSORY DWELLING UNIT. An accessory dwelling unit that is no more than 500 square feet in size and is contained entirely within an existing single- family structure. A junior accessory dwelling unit may include separate sanitation facilities, or may share sanitation facilities with the existing structure.

LIVING AREA. The interior habitable area of a dwelling unit including basements and attics but does not include a garage or any accessory structure.

MAIN UNIT. The existing single-family or multiple-family dwelling unit currently on the lot.

  1. General Requirements. An accessory dwelling unit may be allowed by administrative use permit in single-family and multiple-family zoning districts. No building permit shall be issued for an accessory dwelling unit until an administrative use


permit has been approved by the Zoning Administrator. A building permit shall be issued within 120 days of receipt of an application if all of the following development standards are met:

  1. The lot is zoned for single-family or multi-family residential use and is improved with a single-family dwelling unit.

  2. There shall be no more than one accessory dwelling unit per legal parcel.

  3. The lot on which the accessory dwelling unit is to be placed shall not be subdivided and neither unit can be sold independently of the other. The City shall require recordation of a deed restriction setting forth this subdivision limitation.

  4. The lot on which an accessory dwelling unit is to be placed must be able to provide adequate sewer and water services for both the existing primary dwelling unit and the accessory dwelling unit as determined by the City Engineer. Approval by the Contra Costa County Health Department shall be required if a private sewage disposal system or well system is being used.

  5. The accessory dwelling unit is architecturally compatible with the main unit, and the development of the accessory dwelling unit will maintain the appearance of a single-family residence (if located in a single-family neighborhood or zoning district);

  6. The total combined maximum lot coverage ratio for the existing dwelling unit and the accessory dwelling unit and all accessory buildings located on the lot shall not exceed 60%;

  7. The accessory dwelling unit may either be attached to the main unit, located within the living area of the main unit, or be detached from the main unit;

  8. The floor area of an attached accessory dwelling unit may not exceed 50% of the floor area of the main unit, with a maximum increase in floor area of 1,200 square feet;

  9. The total floor area for a detached accessory dwelling unit shall not exceed 1,200 square feet.

  10. The floor area of a junior accessory dwelling unit may not exceed 500 square feet;

  11. Height, setback, uniform building codes, architectural review, site plan review, and other similar land use requirements of this Code pertaining to main units shall apply to accessory dwelling units. A setback of no more than five feet from the side and rear lot lines shall be required for an accessory dwelling unit that is constructed above a garage. No setback shall be required for an existing garage that is converted to an accessory dwelling unit.

  12. No passageway shall be required in conjunction with construction of an accessory dwelling unit.

  13. Junior accessory dwelling units are limited to one per residential lot zoned for single-family residences with a single-family residence already built on the lot.

  14. Junior accessory dwelling units must be constructed within the existing walls of the structure and must include an existing bedroom.

  15. Junior accessory dwelling units must include a separate entrance from the main entrance to the structure, with an interior entry to the main living area.


  1. Junior accessory dwelling units may include separate sanitation facilities, or may share sanitation facilities with the existing structure.

  2. Junior accessory dwelling units must include an efficiency kitchen, which shall include:

    1. a sink with a maximum waste line diameter of 1.5 inches;

    2. a cooking facility with appliances that do not require electrical service greater than 120 volts, or natural gas or propane;

    3. a food preparation counter and storage cabinets that are of reasonable size in relation to junior accessory dwelling unit.

  3. Parking.

    1. One additional standard off street parking space shall be provided per unit or per bedroom. The additional space may be in tandem, or on an existing driveway.

    2. When a garage, carport, or covered parking structure is demolished in conjunction with the construction of an accessory dwelling unit, and the off- street parking spaces are required to be replaced per the requirements of §9- 5.1703.1, the replacement spaces may be located in any configuration on the same lot as the accessory dwelling unit, including, but not limited to, as covered spaces, uncovered spaces, or tandem spaces.

    3. The requirement for off-street parking may be waived for an accessory dwelling unit in any of the following instances:

      1. Lots developed prior to January, 1964, that have a minimum parcel size of less than 6,000 square feet, provided that compliance with the parking requirements of this section could not be accomplished;

    4. Parking standards shall not be imposed in the following instances:

      1. The accessory dwelling unit is a Junibr Accessory Dwelling as defined in this section or located in an existing accessory structure;

      2. The accessory dwelling unit is located within one-half mile of public transit;

      3. There is a car share vehicle located within one block of the accessory dwelling unit.

      4. The acce’sso dwelling unit is located within an architecturally and historically significant historic district.

      5. When on-street parking permits are required but not offered to the occupant of the accessory dwelling unit.

  4. The rear yard setback for accessory dwelling units may be reduced to 10 feet. Either the accessory dwelling unit or the main unit may be permitted to face the rear of the other structure, and the accessory dwelling unit may be permitted closer than 10 feet from the main unit where it can be shown that the site design will be improved;

  5. Accessory dwelling units are not required to provide fire sprinklers if they are not required for the primary residence;

  6. The main unit shall comply with applicable Building Code requirements for detached dwellings.

  7. The accessory dwelling unit shall have a permanent foundation.


  1. Residential Allocation Exemption. The issuance of administrative use permits for accessory dwelling units shall be exempt from the provisions of Article 40 of this Code, and such permits are exempt from any other growth control limits. This provision is a requirement of state law (Chapter 1062 of the 2002 Statutes). If such requirement is rescinded, this exemption may be eliminated by the City Council.

  1. Occupancy. The owner of the parcel upon which the accessory dwelling unit or junior accessory dwelling unit is located must occupy either the main unit or the accessory dwelling unit or junior accessory dwelling unit, as applicable. Accessory dwelling units may be used for rentals of terms longer than 30 days. Owner occupancy of a junior accessory dwelling unit shall not be required if the owner is another governmental agency, land trust, or housing organization.

  1. Deed Restrictions. Before obtaining a building permit for an accessory dwelling unit, the applicant shall do the following:

  1. Enter into an agreement of restrictions with the City that refers to the deed under which the property was acquired by the applicant and provides the following:

    1. The second unit shall not be sold separately;

    2. The second unit is restricted to the maximum size allowed under Ordinance Code Section § 9-5.3805 (C);

    3. The restrictions are binding upon any successor in ownership of the property and lack of compliance may result in legal action by the County against the property owner.

  2. Record the agreement with the County Recorder.

  3. Prepare a disclosure statement that shall be included in any future offer or sale documents. The statement shall read as follows: “You are purchasing a property with a permit for a second residential unit. This pencil c:arries with it certain restrictions that must be met by the owner of the pr,operI:y. You are prohibited from selling the second unit separately. The second unit is restricted to the maximum size allowed under City of Antioch Zoning Ordinance Cod5 Section § 9-5.3805 (C). The permit is available from the current owner or fro’ri the City of Antioch Community Development Department.”

  1. This section is adopted consistent with, and as required by, state law.


Pursuant to Public Resources Code section 21080.17, the adoption of an ordinance to implement the provisions of Government Code Section 65852.1 and Section 65852.2 is exempt from the California Environmental Quality Act (CEQA).

SECTION 6. Publication; Effective Date.

This ordinance shall take effect and be enforced thirty (30) days from and after the date of its adoption and shall be published once within fifteen (15) days upon

passage and adoption in a newspaper of general circulation printed and published in the City of AntiOCh.

SECTION 7. Severability.

Should any provision of this Ordinance, or its application to any person or circumstance, be determined by a court of competent jurisdiction to be unlawful, unenforceable or otherwise void, that determination shall have no effect on any other provision of this Ordinance or the application of this Ordinance to any other person or circumstance and, to that end, the provisions hereof are severable.

I HEREBY CERTIFY that the foregoing Ordinance was introduced at a regular meeting of the City Council of the City of Antioch held on the 13’h day of December, and

passed and adopted at a regular meeting thereof, held on the 10tday of January 2017,

by the following vote:

AYES: Council Members Wilson, Thorpe, Tiscareno, Ogorchock, and Mayor Wright

NOES: None



Arne Simons-en, City Clerk of the City of Antioch