7.030 Accessory Dwelling Units.

All accessory dwelling units must comply with the following standards:

A. Zoning. An accessory dwelling unit may be created within a residential or mixed-use zone, including planned

unit developments.

B. Type of Unit. An accessory dwelling may be created within an existing or proposed principal dwelling or

accessory structure on the property; may be added to a principal dwelling or accessory structure; or may be built

as a structure separate from any existing or proposed structure on the property. Accessory dwelling units

proposed in multifamily dwelling structures must comply with state building standards for dwellings and may not

convert portions of the existing structure that are used for livable space.

C. Number of Units Allowed. Notwithstanding the development standards included in this section or elsewhere in

the Implementing Zoning Ordinance, the requirements for the number of accessory dwelling units allowed on a lot

are as follows:

 1.   Single-Family Lots. One detached accessory dwelling unit is permitted on a lot with a proposed or existing

 single-family dwelling.

One accessory dwelling unit and one junior accessory dwelling unit may be permitted on a lot with a

proposed or existing single-family dwelling if all of the following standards are met:

       a.   Either the accessory dwelling unit or junior accessory dwelling unit is within the existing or proposed

      single-family dwelling or accessory structure on the lot;

      b.  Any addition beyond the existing single-family dwelling or accessory structure to accommodate the

     accessory dwelling unit or junior accessory dwelling unit does not exceed 150 square feet and is limited

     to accommodate ingress and egress;

        c.   The accessory dwelling unit or junior accessory dwelling has exterior access from the existing or

    proposed single-family dwelling;

      d.  The side and rear yard setbacks comply with all applicable Qre and safety requirements; and

       e.  The junior accessory dwelling unit meets all other requirements of Section 7.035.

 2.   Multifamily Lots. One accessory dwelling unit is permitted on a lot with a proposed or existing multifamily

 dwelling.

The Petaluma Implementing Zoning Ordinance is current through Ordinance 2907, passed September 8, 2025.

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A maximum of two detached accessory dwellings are permitted on a multifamily lot if each unit is limited to

16 feet in height and provides four-foot side and rear yard setbacks.

   If the accessory dwelling units are provided within an existing multifamily dwelling structure, the maximum

number of accessory dwelling units may not exceed 25 percent of the existing number of multifamily dwelling

 units, or one unit, whichever is greater.

D. Size of Unit. The maximum allowable living area of an accessory dwelling unit is 1,000 square feet; provided,

however, that if a proposed accessory dwelling unit is to be attached to an existing or proposed primary residence,

then the accessory dwelling unit total living area may not exceed 50 percent of the total living area of the primary

residence, unless the accessory dwelling unit has a total living area no greater than 800 square feet, a height no

greater than 16 feet, and minimum four-foot side and rear yard setbacks. “Living area” is the interior habitable

area of the accessory unit including basements and attics but not including garages. Living area shall be measured

from the interior side of the exterior walls of the building.

E. Existing Parking. When a garage, carport, or covered parking structure is demolished or converted in

conjunction with the establishment of an accessory dwelling unit the oT-street parking spaces formerly provided

by the demolished structure are not required to be replaced. If replaced, parking may be located in any

conQguration on the same lot as the accessory dwelling unit, including, but not limited to, as covered spaces,

uncovered spaces, or tandem spaces, or by the use of mechanical automobile parking lifts (Consistent with Section

11.070).

F. Foundation Required. Accessory dwelling units must be permanent structures located on a permanent

foundation.

G. Setbacks. An accessory dwelling unit must provide setbacks of no less than four feet from the side and rear lot

lines. No setback shall be required for the conversion or in-kind reconstruction of existing living area or

noncomplying detached structures to accommodate a new accessory dwelling unit. In-kind reconstruction shall

mean the same location, building footprint and height. Any construction proposing expansion to a nonconforming

structure, such as a second story, must provide setbacks of no less than four feet from the side and rear lot lines.

H. Parking. No additional parking is required for new accessory dwelling units.

I. Open Space. Parcels on which accessory dwellings are built shall have a minimum of 100 square feet of

useable open space available for use by occupants of the unit, independent of the primary residence’s

requirement.

J. Development Standard Exceptions. Limits on lot coverage, Roor area ratio (FAR), and open space do not apply to

accessory dwelling units that are less than 800 square feet, do not exceed 16 feet in height, provide minimum

four-foot side and rear yard setbacks, and comply with all other local development standards. On multifamily

development lots this exception may only apply to two detached units that meet the scale and setback parameters

noted in this section.

K. Fire Sprinklers and Fire Attenuation. Accessory dwelling units shall not be required to provide Qre sprinklers if

Qre sprinklers are not required for the primary residence.

The Petaluma Implementing Zoning Ordinance is current through Ordinance 2907, passed September 8, 2025.

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L. Architectural Compatibility. An accessory dwelling is encouraged to be designed to be compatible with the

architectural richness of existing development in the immediate vicinity and principal dwelling on the site.

M. Privacy. New accessory dwellings constructed above the ground Roor shall also be designed to reasonably

preserve the privacy of adjacent property owners. Appropriate design techniques to preserve privacy include

obscured glazing, window placement above eye level, screening treatments, or locating balconies, windows and

doors toward the existing on-site residence.

N. Construction Prior to Principal Dwelling. A certiQcate of occupancy for an accessory dwelling unit may not be

issued before the issuance of a certiQcate of occupancy for the primary dwelling.

O. Historic. The following criteria apply to all applications for accessory dwelling units on designated landmark

sites or within a designated historic district:

 1.  The accessory dwelling unit shall not include the use of plastic or vinyl in exterior materials, architectural

 features, windows, fencing, or other treatment;

 2.  The accessory dwelling unit shall not be a replica of the architectural style of the historic primary

 structure on the site; and

 3.  The accessory dwelling unit must demonstrate architectural compatibility with the existing site or district

by complying with one of the two requirements listed below:

       a.   Matching each of the following qualities of the accessory dwelling unit to the proposed or existing

    primary dwelling unit: (1) color, (2) siding material and pattern, and (3) window type; or

      b.   Submittal of a historic resource survey by a qualiQed professional that concludes the proposed

     accessory dwelling unit will not negatively impact historic resources on the property or in the district and

        will be consistent with the Secretary of the Interior Standards for Treatment of Historic Properties.

P. Rentals. All accessory dwelling units permitted after September 7, 2017, shall only be rented for a term of

more than 30 days. No accessory dwelling units permitted after September 7, 2017, shall be permitted as a short

term vacation rental under Section 7.110.

Q. Ownership. Accessory dwelling units may be rented separate from the primary residence, but may not be sold

or otherwise conveyed separate from the primary residence unless all the following criteria are met:

 1.  The property was built or developed by a qualiQed nonproQt corporation.

 2.   There is an enforceable restriction on the use of the land pursuant to a recorded contract between the

qualiQed buyer and the qualiQed nonproQt corporation that satisQes all of the requirements speciQed in

paragraph (10) of subdivision (a) of Section 402.1 of the Revenue and Taxation Code.

       a.  A “qualiQed buyer” means persons and families of low or moderate income, as that term is deQned

      in Section 50093 of the California Health and Safety Code.

The Petaluma Implementing Zoning Ordinance is current through Ordinance 2907, passed September 8, 2025.

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      b.  A “qualiQed nonproQt corporation” means a nonproQt corporation organized pursuant to Section

      501(c)(3) of the Internal Revenue Code that has received a welfare exemption under Section 214.15 of

     the Revenue and Taxation Code for properties intended to be sold to low-income families who

      participate in a special no-interest loan program.

 3.  The property is held pursuant to a recorded tenancy in common agreement that includes all of the

 following:

       a.  The agreement allocates to each qualiQed buyer an undivided, unequal interest in the property

    based on the size of the dwelling each qualiQed buyer occupies.

      b.  A repurchase option that requires the qualiQed buyer to Qrst oTer the qualiQed nonproQt

     corporation to buy the property if the buyer desires to sell or convey the property.

        c.  A requirement that the qualiQed buyer occupy the property as the buyer’s principal residence.

      d.   ATordability restrictions on the sale and conveyance of the property that ensure the property will be

     preserved for low-income housing for 45 years for owner-occupied housing units and will be sold or

     resold to a qualiQed buyer.

 4.  A grant deed naming the grantor, grantee, and describing the property interests being transferred shall

be recorded in the county in which the property is located. A preliminary change in ownership report shall be

Qled concurrently with this grant deed pursuant to Section 480.3 of the Revenue and Taxation Code.

 5.   Notwithstanding Section 65852.2(f)(2)(A) of the California Government Code, if requested by a utility

 providing service to the primary residence, the accessory dwelling unit has a separate water, sewer, or

 electrical connection to that utility. (Ord. 2738 § 3, 2020; Ord. 2711 § 3, 2020; Ord. 2690 § 2, 2019.)