(a) Subject to subdivision (b), a local agency may establish minimum and maximum unit size requirements for both attached and detached accessory dwelling units.

(b) Notwithstanding subdivision (a), a local agency shall not establish by ordinance any of the following:

(1) A minimum square footage requirement for either an attached or detached accessory dwelling unit that prohibits an efficiency unit.

(2) A maximum square footage requirement for either an attached or detached accessory dwelling unit that is less than either of the following:

(A) Eight hundred fifty square feet.

(B) One thousand square feet for an accessory dwelling unit that provides more than one bedroom.

(3) Any requirement for a zoning clearance or separate zoning review or any other minimum or maximum size for an accessory dwelling unit, size based upon a percentage of the proposed or existing primary dwelling, or limits on lot coverage, floor area ratio, open space, front setbacks, and minimum lot size, for either attached or detached dwellings that does not permit at least an 800 square foot accessory dwelling unit with four-foot side and rear yard setbacks to be constructed in compliance with all other local development standards.

(4) Any height limitation that does not allow at least the following, as applicable:

(A) A height of 16 feet for a detached accessory dwelling unit on a lot with an existing or proposed single family or multifamily dwelling unit.

(B) A height of 18 feet for a detached accessory dwelling unit on a lot with an existing or proposed single family or multifamily dwelling unit that is within one-half of one mile walking distance of a major transit stop or a high-quality transit corridor, as those terms are defined in Section 21155 of the Public Resources Code. A local agency shall also allow an additional two feet in height to accommodate a roof pitch on the accessory dwelling unit that is aligned with the roof pitch of the primary dwelling unit.

(C) A height of 18 feet for a detached accessory dwelling unit on a lot with an existing or proposed multifamily, multistory dwelling.

(D) A height of 25 feet or the height limitation in the local zoning ordinance that applies to the primary dwelling, whichever is lower, for an accessory dwelling unit that is attached to a primary dwelling. This subparagraph shall not require a local agency to allow an accessory dwelling unit to exceed two stories.

(a) When a local agency that has not adopted an ordinance governing accessory dwelling units in accordance with Section 66314 receives an application for a permit to create or serve an accessory dwelling unit pursuant to this article, the local agency shall approve or disapprove the application ministerially without discretionary review pursuant to Section 66317. The permitting agency shall either approve or deny the application to create or serve an accessory dwelling unit or a junior accessory dwelling unit within 60 days from the date the permitting agency receives a completed application if there is an existing single-family or multifamily dwelling on the lot. If the permit application to create or serve an accessory dwelling unit or a junior accessory dwelling unit is submitted with a permit application to create or serve a new single-family or multifamily dwelling on the lot, the permitting agency may delay approving or denying the permit application for the accessory dwelling unit or the junior accessory dwelling unit until the permitting agency approves or denies the permit application to create or serve the new single-family or multifamily dwelling, but the application to create or serve the accessory dwelling unit or junior accessory dwelling unit shall still be considered ministerially without discretionary review or a hearing. If the applicant requests a delay, the 60-day time period shall be tolled for the period of the delay. If the local agency has not approved or denied the completed application within 60 days, the application shall be deemed approved.

(b) If a permitting agency denies an application for an accessory dwelling unit or junior accessory dwelling unit pursuant to subdivision (a), the permitting agency shall, within the time period described in subdivision (a), return in writing 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.

An accessory dwelling unit that conforms to Section 66314 shall be deemed to be an accessory use or an accessory building and shall not be considered to exceed the allowable density for the lot upon which it is located, and shall be deemed to be a residential use that is consistent with the existing general plan and zoning designations for the lot. The accessory dwelling unit shall not be considered in the application of any local ordinance, policy, or program to limit residential growth.

(a) A permit application for an accessory dwelling unit or a junior accessory dwelling unit shall be considered and approved ministerially without discretionary review or a hearing, notwithstanding Section 65901 or 65906 or any local ordinance regulating the issuance of variances or special use permits. The permitting agency shall either approve or deny the application to create or serve an accessory dwelling unit or a junior accessory dwelling unit within 60 days from the date the permitting agency receives a completed application if there is an existing single-family or multifamily dwelling on the lot. If the permit application to create or serve an accessory dwelling unit or a junior accessory dwelling unit is submitted with a permit application to create a new single-family or multifamily dwelling on the lot, the permitting agency may delay approving or denying the permit application for the accessory dwelling unit or the junior accessory dwelling unit until the permitting agency approves or denies the permit application to create the new single-family or multifamily dwelling, but the application to create or serve the accessory dwelling unit or junior accessory dwelling unit shall be considered without discretionary review or hearing. If the applicant requests a delay, the 60-day time period shall be tolled for the period of the delay. If the local agency has not approved or denied the completed application within 60 days, the application shall be deemed approved. A local agency may charge a fee to reimburse it for costs incurred to implement this section, including the costs of adopting or amending any ordinance that provides for the creation of an accessory dwelling unit.

(b) If a permitting agency denies an application for an accessory dwelling unit or junior accessory dwelling unit pursuant to subdivision (a), the permitting agency shall, within the time period described in subdivision (a), return in writing 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) No local ordinance, policy, or regulation, other than an accessory dwelling unit ordinance consistent with this article shall be the basis for the delay or denial of a building permit or a use permit under this section.

An existing accessory dwelling unit ordinance governing the creation of an accessory dwelling unit by a local agency or an accessory dwelling ordinance adopted by a local agency shall provide an approval process that includes only ministerial provisions for the approval of accessory dwelling units and shall not include any discretionary processes, provisions, or requirements for those units, except as otherwise provided in this article. If a local agency has an existing accessory dwelling unit ordinance that fails to meet the requirements of this article, that ordinance shall be null and void and that agency shall thereafter apply the standards established in this article for the approval of accessory dwelling units, unless and until the agency adopts an ordinance that complies with this article.

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.

A local agency may, by ordinance, provide for the creation of accessory dwelling units in areas zoned to allow single-family or multifamily dwelling residential use. The ordinance shall do all of the following:

(a) Designate areas within the jurisdiction of the local agency where accessory dwelling units may be permitted. The designation of areas may be based on the adequacy of water and sewer services and the impact of accessory dwelling units on traffic flow and public safety. A local agency that does not provide water or sewer services shall consult with the local water or sewer service provider regarding the adequacy of water and sewer services before designating an area where accessory dwelling units may be permitted.

(b)

(1) Impose objective standards on accessory dwelling units that include, but are not limited to, parking, height, setback, landscape, architectural review, maximum size of a unit, and standards that prevent adverse impacts on any real property that is listed in the California Register of Historical Resources. These standards shall not include requirements on minimum lot size.

(2) Notwithstanding paragraph (1), a local agency may reduce or eliminate parking requirements for any accessory dwelling unit located within its jurisdiction.

(c) Provide that accessory dwelling units do not exceed the allowable density for the lot upon which the accessory dwelling unit is located, and that accessory dwelling units are a residential use that is consistent with the existing general plan and zoning designation for the lot.

(d) Require the accessory dwelling units to comply with all of the following:

(1) Except as provided in Article 4 (commencing with Section 66340), the accessory dwelling unit may be rented separate from the primary residence, but shall not be sold or otherwise conveyed separate from the primary residence.

(2) The lot is zoned to allow single-family or multifamily dwelling residential use and includes a proposed or existing dwelling.

(3) The accessory dwelling unit is either attached to, or located within, the proposed or existing primary dwelling, including attached garages, storage areas or similar uses, or an accessory structure or detached from the proposed or existing primary dwelling and located on the same lot as the proposed or existing primary dwelling, including detached garages.

(4) If there is an existing primary dwelling, the total floor area of an attached accessory dwelling unit shall not exceed 50 percent of the existing primary dwelling.

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

(6) No passageway shall be required in conjunction with the construction of an accessory dwelling unit.

(7) No setback shall be required for an existing living area or accessory structure or a structure constructed in the same location and to the same dimensions as an existing structure that is converted to an accessory dwelling unit or to a portion of an accessory dwelling unit, and a setback of no more than four feet from the side and rear lot lines shall be required for an accessory dwelling unit that is not converted from an existing structure or a new structure constructed in the same location and to the same dimensions as an existing structure.

(8) Local building code requirements that apply to detached dwellings, except that the construction of an accessory dwelling unit shall not constitute a Group R occupancy change under the local building code, as described in Section 310 of the California Building Code (Title 24 of the California Code of Regulations), unless the building official or enforcement agency of the local agency makes a written finding based on substantial evidence in the record that the construction of the accessory dwelling unit could have a specific, adverse impact on public health and safety. Nothing in this paragraph shall be interpreted to prevent a local agency from changing the occupancy code of a space that was unhabitable space or was only permitted for nonresidential use and was subsequently converted for residential use pursuant to this article.

(9) Approval by the local health officer where a private sewage disposal system is being used, if required.

(10)

(A) Parking requirements for accessory dwelling units shall not exceed one parking space per accessory dwelling unit or per bedroom, whichever is less. These spaces may be provided as tandem parking on a driveway.

(B) Off­street parking shall be permitted in setback areas in locations determined by the local agency or through tandem parking, unless specific findings are made that parking in setback areas or tandem parking is not feasible based upon specific site or regional topographical or fire and life safety conditions.

(C) This subparagraph shall not apply to an accessory dwelling unit that is described in Section 66322.

(11) When a garage, carport, covered parking structure, or uncovered parking space is demolished in conjunction with the construction of an accessory dwelling unit or converted to an accessory dwelling unit, the local agency shall not require that those offstreet parking spaces be replaced.

(12) Accessory dwelling units shall not be required to provide fire sprinklers if they are not required for the primary residence. The construction of an accessory dwelling unit shall not trigger a requirement for fire sprinklers to be installed in the existing primary dwelling.

(e) Require that a demolition permit for a detached garage that is to be replaced with an accessory dwelling unit be reviewed with the application for the accessory dwelling unit and issued at the same time.

(f) An accessory dwelling unit ordinance shall not require, and the applicant shall not be otherwise required, to provide written notice or post a placard for the demolition of a detached garage that is to be replaced with an accessory dwelling unit, unless the property is located within an architecturally and historically significant historic district.

For purposes of this chapter:

(a) “Accessory dwelling unit” means an attached or a detached residential dwelling unit that provides complete independent living facilities for one or more persons and is located on a lot with a proposed or existing primary residence. It shall include permanent provisions for living, sleeping, eating, cooking, and sanitation on the same parcel as the single-family or multifamily dwelling is or will be situated. An accessory dwelling unit also includes the following:

(1) An efficiency unit.

(2) A manufactured home, as defined in Section 18007 of the Health and Safety Code.

(b) “Accessory structure” means a structure that is accessory and incidental to a dwelling located on the same lot.

(c) “Efficiency unit” has the same meaning as defined in Section 17958.1 of the Health and Safety Code.

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

(e) “Livable space” means a space in a dwelling intended for human habitation, including living, sleeping, eating, cooking, or sanitation.

(f) “Living area” means the interior habitable area of a dwelling unit, including basements and attics, but does not include a garage or any accessory structure.

(g) “Local agency” means a city, county, or city and county, whether general law or chartered.

(h) “Nonconforming zoning condition” means a physical improvement on a property that does not conform to current zoning standards.

(i) “Objective standards” means standards that involve no personal or subjective judgment by a public official and are uniformly verifiable by reference to an external and uniform benchmark or criterion available and knowable by both the development applicant or proponent and the public official prior to submittal.

(j) “Passageway” means a pathway that is unobstructed clear to the sky and extends from a street to one entrance of the accessory dwelling unit.

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

(l) “Proposed dwelling” means a dwelling that is the subject of a permit application and that meets the requirements for permitting.

(m) “Public transit” means a location, including, but not limited to, a bus stop or train station, where the public may access buses, trains, subways, and other forms of transportation that charge set fares, run on fixed routes, and are available to the public.

(n) “Tandem parking” means that two or more automobiles are parked on a driveway or in any other location on a lot, lined up behind one another.