Martinez Municipal Code § 22.43.040 Quantity of units

This Chapter is intended to comply with State Law (including, but not limited to, California Government Code Sections 66310 through 66342), by allowing accessory dwelling units (ADU) and junior accessory dwelling units (JADU) through ministerial review, subject to meeting the objective design and development standards prescribed below. In the event of any conflict or inconsistency between this Chapter and State law, or this Chapter and other Sections in the Municipal Code, then the more permissive regulations shall prevail.

(Ord. No. 1447, § 10, 7/19/2023; Ord. No. 1474, 7/16/2025; Ord. No. 1485, 3/18/2026; Ord. No. 1490, 9/2/2026)

State Law identifies two separate types of ADUs which are relevant for the purposes of this Chapter. Definitions for these types of ADUs, including "Local ADUs" and "State ADUs," are provided in Chapter 22.04 (Definitions). Unless specified, the requirements and development standards of this Chapter shall apply to both a Local ADU and State ADU.

(Ord. No. 1490, 9/2/2026)

A. Any ADU may be permitted:

1. On any lot zoned for a residential use, or any non-residentially zoned lot which is currently occupied with a single-family dwelling or multifamily dwellings.

2. On any lot zoned or occupied by a religious institution, as defined in Chapter 22.04 (Definitions).

B. ADUs shall not be located in the following locations:

1. In areas encumbered by a recorded easement, including but not limited to, public utility easements, conservation easements, access easements, pedestrian pathway easements and open space easements; or

2. In areas that extend into a creek bank.

(Ord. No. 1447, § 10, 7/19/2023; Ord. No. 1463, § XVII, 10/23/2024; Ord. No. 1485, 3/18/2026; Ord. No. 1490, 9/2/2026; Ord. No. 1490, 9/2/2026. Formerly 22.43.020)

The following number of ADUs and JADUs shall be the maximum number of ADUs and JADUs on lots subject to this Chapter:

A. Lot with a proposed or existing single-family dwelling:

1. One Local ADU that is either:

a. Attached to, or located within, the proposed or existing primary dwelling, including attached garages, storage areas or similar uses; or

b. Attached to, or located within, an attached or detached accessory structure; or

c. Detached from the proposed or existing primary dwelling and located on the same lot as the proposed or existing primary dwelling.

2. One attached State ADU within the proposed space of a single-family dwelling or existing space of a single-family dwelling or accessory structure;

3. One JADU; and

4. One detached new construction State ADU.

B. Lot with existing multifamily dwellings or mixed-use development with multiple dwelling units:

1. At least one State ADU and up to 25% of the total number of existing dwelling units on the lot converted from non-habitable portions of the existing primary structure that are not within the living space of a dwelling unit (e.g., basement, attic, garages storage room, or commercial spaces) or the non-residential portions of a mixed-use building;

2. Up to eight detached State ADUs, but shall be limited to the number of existing multifamily dwelling units on the lot; and

3. One Local ADU that is either:

a. Attached to, or located within, the proposed or existing primary dwelling, including attached garages, storage areas or similar uses; or

b. Attached to, or located within, an attached or detached accessory structure; or

c. Detached from the proposed or existing primary dwelling and located on the same lot as the proposed or existing primary dwelling.

C. Lot with proposed multifamily dwellings or mixed-use development with multiple dwelling units:

1. Up to two detached ADUs; and

2. One local ADU that is either:

a. Attached to, or located within, the proposed or existing primary dwelling, including attached garages, storage areas or similar uses; or

b. Attached to, or located within, an attached or detached accessory structure; or

c. Detached from the proposed or existing primary dwelling and located on the same lot as the proposed or existing primary dwelling.

D. Lot with religious institution: up to four local ADUs, subject to the following exceptions:

1. When a lot contains a religious institution and a single-family and/or multifamily dwelling, the maximum number of ADU(s) permitted shall be associated with either the religious institution use or the residential use(s), whichever permits more.

2. When a religious institution occupies multiple lots, only one of these lots shall be eligible for the ADU(s).

(Ord. No. 1447, § 10, 7/19/2023; Ord. No. 1463, § XVII, 10/23/2024; Ord. No. 1469, § IX, 4/2/2025; Ord. No. 1485, 3/18/2026; Ord. No. 1490, 9/2/2026. Formerly 22.43.030)

A. Minimum Size. An ADU/JADU shall be a minimum of 150 square feet or the size necessary to accommodate an efficiency unit as defined by California Health and Safety Code Section 17958.1, whichever is greater.

B. Maximum Size.

1. State ADU.

a. New Construction ADU. The total floor area of a new construction attached or detached ADU shall not exceed 800 square feet, excluding any garage area.

b. Conversions. Conversions of existing structures or detached accessory structures shall not be limited in size and shall comply with Subsection C below.

2. JADU. The total floor area of a JADU shall not be more than 500 square feet of interior living space, excluding any shared sanitation facility within the primary dwelling structure.

3. Local ADU.

a. Detached ADU. The total floor area of a detached ADU shall not exceed 1,200 square feet, excluding any garage area.

b. Attached ADU. The total floor area of an attached ADU shall not exceed 1,200 square feet, or shall not exceed 50% of the existing primary dwelling square footage unless it would preclude the construction of an ADU of at least 800 square feet, whichever is less.

C. Conversion Restrictions. An ADU created entirely through conversion of an existing permitted structure is allowed a physical addition of no more than 150 square feet and shall be limited to accommodating ingress and egress, subject to all other applicable provisions of this Chapter. The conversion of an existing permitted accessory structure or a portion of an existing primary structure to an ADU is not subject to unit size requirements.

(Ord. No. 1447, § 10, 7/19/2023; Ord. No. 1474, 7/16/2025; Ord. No. 1485, 3/18/2026; Ord. No. 1490, 9/2/2026. Formerly 22.43.040)

A. State ADUs. Newly constructed State ADUs, whether attached, detached, converted, shall be exempt from the maximum lot coverage or floor area ratio allowed in the zoning or overlay district.

B. Local ADUs. Newly constructed attached or detached local ADUs shall be subject to the maximum lot coverage or floor area ratio allowed in the zoning or overlay district unless it would preclude the construction of a local ADU that is at least 800 square feet.

(Ord. No. 1490, 9/2/2026)

A. Front.

1. State ADUs. No front setback required for either an attached or detached State ADU.

2. Local ADUs. Both attached and detached local ADUs shall be subject to the same front setback requirements as the primary dwelling unless it would preclude the construction of a local ADU that is at least 800 square feet and the local ADU could not be reasonably accommodated elsewhere on the site.

B. Side. A setback of no less than four feet from the side lot line shall be required for either an attached or detached State or local ADU.

C. Rear. A setback of no less than four feet from the rear lot line shall be required for either an attached or detached State or local ADU.

D. Expansion of Converted Existing Structures. The first floor of an existing permitted structure which has setbacks of less than four feet and is planned for conversion into a State or local ADU can be expanded, so long as the expansion does not result in additional encroachment into the required setbacks.

E. Architectural Features. Architectural features including sills, eave overhangs, awnings, and cornices may extend into a required setback or space between buildings not more than 18 inches.

(Ord. No. 1447, § 10, 7/19/2023; Ord. No. 1480, 12/10/2025; Ord. No. 1485, 3/18/2026; Ord. No. 1490, 9/2/2026. Formerly 22.43.050)

Both attached and detached State and local ADUs shall not encroach within the sight distance area, as established by the California Department of Transportation Highway Design Manual, Chapter 400, Section 405, to protect the health and safety of the public.

(Ord. No. 1485, 3/18/2026; Ord. No. 1490, 9/2/2026. Formerly 22.43.055)

A. State ADUs. Detached State ADUs shall not be subject to any building separation standards, but shall comply with any fire-rating requirements described below in subsection C of this section.

B. Local ADUs. For any detached local ADU, the distance between the local ADU and any other structures shall be at least five feet.

C. Fire-Rating Requirements. All detached State or local ADUs located closer than five feet to any other structures without an automatic residential fire sprinkler system shall be subject to a minimum of one-hour fire-resistance rating and shall comply with all California Building Code and California Fire Code fire-rating requirements.

(Ord. No. 1447, § 10, 7/19/2023; Ord. No. 1485, 3/18/2026; Ord. No. 1490, 9/2/2026. Formerly 22.43.060)

Building height shall be measured as the vertical distance from any point on the natural grade, to the topmost point of the building immediately above.

A. Detached ADU.

1. New Construction. A maximum height of 18 feet for a new detached State or local ADU shall be permitted. An additional two feet in height to accommodate a roof pitch on the State or local ADU that is aligned with the roof pitch of the primary dwelling unit shall also be permitted.

2. Addition to an Existing Detached Structure. A State or local ADU which results in an addition to an existing detached accessory structure that is not the primary dwelling or another State or local ADU shall have a maximum height of 25 feet or the height limitation associated with the primary dwelling, whichever is lower.

B. Attachment ADU. A maximum height of 25 feet or the height limitation associated with the primary dwelling, whichever is lower, shall be permitted for a State or local ADU that is attached to a primary dwelling.

(Ord. No. 1447, § 10, 7/19/2023; Ord. No. 1474, 7/16/2025; Ord. No. 1485, 3/18/2026; Ord. No. 1490, 9/2/2026. Formerly 22.43.070)

A. Minimum Parking. A minimum of one independently usable off-street parking space shall be provided for each State or local ADU, which shall be provided in addition to the required parking for the primary residential dwelling(s), except as outlined in subsections C and D of this section. No parking is required for a JADU.

B. Parking Design. This space need not be covered, and shall comply with all development standards set forth in Chapter 22.36 (Off-Street Parking and Loading Facilities), except the space may be compact and/or uncovered. A tandem parking space may also be used to meet the parking requirement for a State or local ADU, providing such space will not encumber access to a required parking space for the primary single-family dwelling.

C. Replacement Parking. When a garage, carport, or covered parking structure is demolished or converted in conjunction with the construction of a State or local ADU or JADU, no parking replacement spaces for the primary residence shall be required. Any other required off-street parking spaces shall be maintained for the primary residence, and may be located in any configuration on the same lot as the State or local ADU, including, but not limited to, as covered spaces, uncovered spaces, tandem spaces, or by the use of mechanical automobile parking lifts. A demolition permit for a detached garage that is to be replaced with a State or local ADU shall be reviewed with the building permit application for the State or local ADU and issued at the same time. The applicant is not required to provide written notice or post a placard for the demolition of a detached garage, that is to be replaced with a State or local ADU, unless the property is located within the Historic Overlay District or another architecturally and historically significant historic district.

D. Parking Exceptions. Off-street parking shall not be required for a State or local ADU in any of the following instances:

1. The State or local ADU has no bedroom (such as a studio unit or efficiency unit).

2. The State or local ADU is located within one-half mile walking distance of public transit, including various means of transportation that charge set fees, run on fixed schedules, and are available to the public.

3. The State or local ADU is located within the Historic Overlay District or another architecturally and historically significant historic district.

4. The State or local ADU is part of the proposed or existing primary dwelling or an accessory structure.

5. When on-street parking permits are required but not offered to the occupant of the State or local ADU.

6. When there is a designated pick-up or drop-off location for car share vehicles located within one block of the State or local ADU.

7. The State or local ADU is consistent with affordability requirements outlined in § 22.43.170.

8. When a building permit application for a State or local ADU is submitted with a building permit application to create a new single-family dwelling or a new multifamily dwelling on the same lot, provided the State or local ADU or the parcel satisfies any other criteria listed under these parking exceptions.

(Ord. No. 1447, § 10, 7/19/2023; Ord. No. 1485, 3/18/2026; Ord. No. 1490, 9/2/2026. Formerly 22.43.080)

The following design standards shall apply to applicable State and local ADUs:

A. Aesthetics. The design of the local ADU shall be as follows:

1. For a detached local ADU, the exterior materials and design shall match the design of any existing primary unit on the property through the use of the same exterior wall materials, identified color tones, window types, door and window trims, roofing materials and roof pitch. The Community and Economic Development Director, Planning Manager, or designee may determine without the requirement for a public hearing or a public review process that similar materials and design substantially comply with this requirement.

2. For an attached local ADU, the exterior materials, windows, and other architectural features shall match the existing structure by employing the same building form, exterior wall materials, color tones, window design, door and window trims, roofing materials and roof pitch. The Community and Economic Development Director, Planning Manager, or designee may determine without the requirement for a public hearing or a public review process that similar materials, windows, or other architectural features substantially comply with this requirement.

B. Lighting. Exterior building lighting shall be fully shielded and downward-facing and limited to one exterior light fixture per exterior doorway, or the minimum necessary to comply with the California Building Standards Code.

C. Utility Connections. All electrical and utility services to a new dwelling unit shall be undergrounded.

(Ord. No. 1447, § 10, 7/19/2023; Ord. No. 1480, 12/10/2025; Ord. No. 1485, 3/18/2026; Ord. No. 1490, 9/2/2026. Formerly 22.43.090)

A. State and local ADUs and JADUs shall have an independently accessible entrance that does not require passage through the primary residence.

B. With the exception of JADUs that do not include separate sanitation facilities, attached State and local ADUs shall not be allowed a connecting doorway or other permanent ingress or egress between the primary dwelling and the State or local ADU.

(Ord. No. 1447, § 10, 7/19/2023; Ord. No. 1485, 3/18/2026; Ord. No. 1490, 9/2/2026. Formerly 22.43.100)

The following privacy standards shall apply to all local ADUs:

A. Windows. Local ADUs that do not meet the setback requirements that would apply to a primary dwelling in the same district shall require windows on the second story or above that face neighboring property lines to:

1. Be a clerestory with a minimum sill height of six feet above the subject interior floor elevation; or

2. Have frosted or opaque glass and not be operable except as required for an ingress/egress requirement pursuant to the California Residential Code.

B. Balconies and Decks. Balconies and decks attached to ADUs shall comply with the setback requirements that apply to a primary dwelling in the same district.

(Ord. No. 1447, § 10, 7/19/2023; Ord. No. 1458, § XII, 5/15/2024; Ord. No. 1480, 12/10/2025; Ord. No. 1485, 3/18/2026; Ord. No. 1490, 9/2/2026. Formerly 22.43.110)

A. Compliance With Building Codes. All State and local ADUs and JADUs shall comply with all applicable requirements of the building code as adopted and enforced at time of submitting a complete application. In cases where a State or local ADU or JADU is to be created through the reconfiguration of a portion of an existing single-family dwelling, both the State or local ADU or JADU and primary dwelling shall be upgraded to comply with such building code requirements, which include but is not limited to noise separation between units sharing common walls, emergency egress and heating/ventilation requirements, as required by the Chief Building Official or designee.

B. Final Building Permit. A final building permit for a State or local ADU or JADU shall not be permitted before a final building permit is issued for the respective primary dwelling, unless the State or local ADU is constructed in a county that is subject to a proclamation of a state of emergency made by the Governor on or after February 1, 2025, if the primary dwelling was substantially damaged or destroyed by an event referenced in the state of emergency, and the State or local ADU has been issued construction permits and passed all required inspections.

C. Permanent Foundation. A permanent foundation shall be required for all attached and detached State or local ADUs and for any State or local ADU or JADU created entirely through conversion to the existing structure with a physical addition.

D. Public Utilities and Services. State or Local ADUs shall be served by public water and sewer and shall have access to an improved public street.

E. Required Facilities. With the exception of JADUs, all attached or detached State or local ADUs must include:

1. Independent facilities for living, sleeping, cooking, and sanitation.

2. A kitchen area containing a refrigerator, sink, and permanently installed cooking appliance, which must include at least a fixed stovetop.

3. A fully plumbed bathroom including sink, shower, and toilet.

4. If a permitted JADU does not include a separate bathroom, the JADU must include a separate entrance from the main entrance to the structure, with an interior entry to the main living area.

F. Fire Sprinklers. All newly constructed or converted State or local ADUs are required to have automatic residential fire sprinklers consistent with California Residential Code Section R313.2, unless the existing primary structure was constructed prior to the requirement for automatic residential sprinkler system. The construction of a State or local ADU shall not trigger a requirement for fire sprinklers to be installed in the existing primary dwelling.

G. Windows. Detached State or local ADUs with a wall(s) located closer than five feet to a primary dwelling shall not include any openings such as windows or doors on the subject wall(s), due to California Building Code requirements.

H. Occupancy. State or local ADUs and JADUs may be rented separately from the primary dwelling. Dwellings with ADUs do not require owner occupancy of either the primary dwelling or State or local ADU. Dwellings with JADUs require owner occupancy of either the primary dwelling or the JADU if the JADU has shared sanitation facilities with the existing structure, but shall not be required if the JADU has separate sanitation facilities or the owner is another governmental agency, land trust, or housing organization. No State or local ADU or JADU shall be rented for a period of less than 31 days and cannot be occupied as a short-term rental unit.

I. Conveyance. State or Local ADUs may be separately conveyed as condominiums under the following requirements:

1. Non-Profit Conveyance: The involvement of qualified nonprofit housing organizations consistent with California Government Code Section 66341.

2. Private Conveyance: A State or local ADU may be conveyed separately from a primary dwelling via a private transaction with implementation of a condominium plan. The conveyance of the State or Local ADU shall also comply with California Government Code Section 66341, the Subdivision Map Act (Division 2 (commencing with Section 66410)), and all objective requirements of Title 21.

J. Common Sanitation Facilities. JADUs are permitted to have common sanitation facilities with the primary dwelling. Any JADU with common sanitation facilities shall have interior access to the primary dwelling.

K. Protected Trees. Where a State or local ADU is proposed within the dripline of a protected tree, as defined in § 8.08.044, an arborist report prepared by a licensed arborist shall be required and all ensuing recommendations shall be followed.

L. Hillside Properties. For areas with slopes greater than 30%, the preparation of a geotechnical investigation report shall be required and all ensuing recommendations shall be followed.

(Ord. No. 1447, § 10, 7/19/2023; Ord. No. 1458, § XII, 5/15/2024; Ord. No. 1485, 3/18/2026; Ord. No. 1490, 9/2/2026. Formerly 22.43.120)

A. Exceptions May Be Granted. The Zoning Administrator may grant an exception to height, size, setback, sight distance, building separation, parking, ingress and egress, privacy, and design standards consistent with the procedures set forth in Chapter 22.45 (Exceptions).

B. Limitations of This Section. Consistent with California Government Code Section 66323, this Section shall not preclude or impede the development of any State ADU and in compliance with all other local development standards.

(Ord. No. 1447, § 10, 7/19/2023; Ord. No. 1485, 3/18/2026; Ord. No. 1490, 9/2/2026. Formerly 22.43.130)

A. Applicability. Applicants that are proposing to deed-restrict a State or local ADU to the following affordability levels are eligible for the bonuses described below:

1. Moderate-income, deed-restricted: Provide affordability between 80% to 120% of area median income with affordability restrictions in place for 55 years.

2. Lower-income, deed-restricted: Provide affordability at less than 80% of area median income with affordability restrictions in place for 35 years.

B. Bonuses. The Community and Economic Development Director, Planning Manager, or designee shall approve the following exceptions:

1. For State and local ADU(s) consistent with the affordability requirements outlined in Subsection A of this section:

a. If the project is located in within a transit priority area, defined by California Public Resources Code Section 21099(a)(7) as an area within one-half mile of a major transit stop that is existing or planned, the applicant shall be allowed one additional unrestricted local ADU for every deed-restricted State or local ADU with no limits so long as the respective amount of deed-restricted State or local ADUs is provided, subject to space limitations and compliance with other standards and requirements of this Chapter.

b. If the project is not located within a transit priority area, the limit shall be one additional deed-restricted local ADU, for a maximum of five ADUs.

2. Waiver from another development standard listed in this chapter that would otherwise make development of a deed-restricted State or local ADU infeasible.

C. Requirements. Property owners shall work with the City to establish an affordable housing program for the deed restricted ADUs, which at a minimum shall establish tenant eligibility, income verification and reporting requirements, and procedures for when a tenant's income raise beyond income limits.

(Ord. No. 1447, § 10, 7/19/2023; Ord. No. 1463, § XVII, 10/23/2024; Ord. No. 1485, 3/18/2026; Ord. No. 1490, 9/2/2026. Formerly 22.43.140)

An application for a State or local ADU or JADU shall be allowed with a building permit. In addition to the normal building permit submittal requirements, a completed application must include, at a minimum:

A. Site Plan.

1. Drawn to scale.

2. Dimensions of the perimeter of parcel on which the proposed dwelling will be located.

3. Indicate the location and dimensioned setbacks of all existing, proposed, and adjacent structures abutting the project site.

4. Data on the floor space of the existing structure(s) and proposed unit.

5. All easements, building envelopes, and special requirements of the subdivision as shown on the final map and improvement plans shall be included.

6. Provide average slope calculations for the project site.

7. Calculations indicating the square footage of the structure and the lot, including calculations on the plan for the percentage of lot area covered by the foundation of the existing and proposed dwelling units.

B. Floor Plans.

1. Each floor and room shall be dimensioned, and the resulting floor area calculation included.

2. The use of each room shall be identified.

3. The size and location of all windows and doors shall be clearly depicted.

C. Elevation Views.

1. Provide north, south, east, and west elevations.

2. Show all heights for all existing and proposed structures on site. Height shall be calculated as the vertical distance of a building at any point, within a given plane, from finished grade to the top of the roof or parapet walls.

3. Show all openings, exterior finishes, original and finish grades, stepped footing outline, roof pitch, and materials.

4. For State or local ADUs and/or JADUs that include modifications to the exterior of the primary structure or new construction, provide elevations showing all openings, exterior finishes, original and finish grades, stepped footing outline, roof pitch, materials and color board for the existing primary structure and the proposed unit.

(Ord. No. 1447, § 10, 7/19/2023; Ord. No. 1485, 3/18/2026; Ord. No. 1490, 9/2/2026. Formerly 22.43.150)

A. Application to be Administratively Approved. All State or local ADUs and JADUs require a building permit. The building permit will be reviewed for compliance with applicable building codes, California Government Code Sections 66310 through 66342, and development and design standards from this Section. If an application to create a State or local ADU or JADU is submitted as part of a project that requires discretionary review, a building permit shall not be issued for the State or local ADU or JADU until the discretionary approval(s) has/have been granted and any applicable appeal periods have expired.

B. Determination of Completeness. The City shall determine whether an application for a State or Local ADU or JADU is complete viand provide written notice to the applicant within 15 business days of receipt of the application. If the City deems the application incomplete, then the City shall provide the applicant with a written list of incomplete items and a description of how the application can be made complete.

C. Approval of ADU. The City shall either approve or deny an application for a State or local ADU or JADU within 60 days from the date the application was determined to be complete if there is an existing single-family or multifamily dwelling on the lot. If the application for a State or local ADU or JADU is submitted with an application to create a new single-family or multifamily dwelling on the lot, then the City may delay approving or denying the application until the City approves or denies the application to create the new single-family or multifamily dwelling, but the application to create or serve the State or local ADU shall be considered without discretionary review or hearing, except as allowed pursuant to § 22.43.160.

D. Approval of Unit Does Not Permit Land Division. Approval of a State or local ADU or JADU shall not be deemed to be a division of land for purposes of California Government Code Section 66410 et seq., or Title 21, nor shall the administrative approval above entitle the applicant to either: (1) such a division of land; or (2) to have each of the dwelling units on the parcel separately assessed for property tax purposes.

(Ord. No. 1447, § 10, 7/19/2023; Ord. No. 1458, § XII, 5/15/2024; Ord. No. 1485, 3/18/2026; Ord. No. 1490, 9/2/2026. Formerly 22.43.160)

See Chapter 15.55 (Residential Amnesty Program for Unpermitted Dwelling Units) for regulations related to legalizing unpermitted dwelling units.

(Ord. No. 1469, § IX, 4/2/2025; Ord. No. 1485, 3/18/2026; Ord. No. 1490, 9/2/2026. Formerly 22.43.170)

All references to State statutes include successor provisions.

(Ord. No. 1485, 3/18/2026; Ord. No. 1490, 9/2/2026. Formerly 22.43.180)