Fresno | ADUs and SB 9

Fresno ADUs and SB 9: Two ADUs per Lot, Junior ADUs, ADU Sales and Two-Unit Projects

An accessory dwelling unit (ADU) is a second, smaller home on a lot that keeps its main home. A junior ADU is a unit of 500 square feet or less built inside the main home. SB 9 (2021) is the state law that lets an owner build two main homes on a single-family lot. Fresno rewrote its ADU rules in July 2025, in Section 15-2754 of the Municipal Code, and handles SB 9 through a City checklist. This page reads both and marks where the City text and state law differ. The California ADU law page covers the state rules in full.

The 2025 Rewrite

Ordinance 2025-024, effective July 27, 2025, "repealed the former § 15-2754, and enacted a new § 15-2754." The former section covered "Second Dwelling Units, Backyard Cottages, and Accessory Living Quarters." The new Section 15-2754 says its purpose is "to allow for the ministerial development of Second Dwelling Units," which means staff approve a plan that meets the written rules, with no hearing. Table 15-4907 lists the permit for a second dwelling unit as a "Building permit" with a "Ministerial" decision.

The section also gives way to the state: "Should there be any conflict with the provisions in this section and those within Government Code Section 66310 et seq., as may be amended, the Government Code shall prevail." That sentence matters in two places below, where the City text is stricter than the statute.

ADUs "may be permitted in any zone district that allows single-unit and multi-unit residential dwellings, mixed-use development, or where a single-unit structure, duplex, or multi-unit structure is either existing or proposed." Junior ADUs "are limited to single-unit districts or where a single-unit dwelling is existing or proposed."

Fresno ADU Rules Summary

Source: Fresno Municipal Code Section 15-2754, Ordinance 2025-024, Supplement 54.

How Many ADUs and How Big

On a lot with one home, the code allows "Up to two ADUs and one JADUs per lot." On a lot with apartments, the detached limit is "Up to eight detached ADUs per lot, not to exceed the number of existing units," and those ADUs "do not need to be detached from each other or other accessory structures on the lot." The same lot may convert non-livable space, "such as enclosed garages, leasing office, common rooms," into ADUs equal to "up to 25 percent of the number of existing units or one ADU, whichever is greater." VanPlex arithmetic: an existing fourplex could add four detached ADUs and one converted ADU.

ADUs sit outside the lot's zoning counts. "Second Dwelling Units are not included in calculations for lot coverage requirements," and "Second Dwelling Units are not included in calculations for density requirements." So an RS-5 lot, where coverage is capped at 60 percent, measures that 60 percent without counting its ADUs.

The size cap is: "Not to exceed 50 percent of the average floor area of the primary unit(s) or 1,400 square feet, whichever is greater." Next to a 2,000 square foot house, 50 percent is 1,000 square feet, so 1,400 is the limit. Next to a 3,200 square foot house, 50 percent is 1,600 square feet, which becomes the limit. Both figures are above the state floor: Government Code 66321 bars a cap below "Eight hundred fifty square feet" or "One thousand square feet" for an ADU with more than one bedroom.

A conversion has its own rule. An ADU made inside an existing home or accessory structure "may expand up to 150 beyond the same physical dimensions of the existing accessory structure for the purpose of accommodating ingress and egress." The printed code leaves out the unit after "150." The state statute that this sentence follows, Government Code 66323, allows "an expansion of not more than 150 square feet beyond the same physical dimensions as the existing accessory structure." Confirm the City's reading before you design to it.

Height, Setbacks and Placement

• Height. "Per the underlying district or 30 feet, whichever is greater. Second Dwelling Units are allowed to be multiple stories or located above the ground floor." Table 15-903-2 sets 35 feet in every RS district, so a two-story ADU over a garage fits. In RM-1 the district height is 40 feet.
• Side and rear setbacks. A setback is the required gap between a building and a lot line. For ADUs it is "Per the underlying base district or four feet, whichever is less." In RS-5, where the interior side setback is 8 feet in total with at least 3 on a side, the ADU may use 3 feet.
• Alleys. "Properties abutting alleys. Zero feet. If the ADU has its main entrance on the alley, however, the setback shall be at least two feet."
• Easements. When a recorded utility easement is present, the setback "shall include such easement even if it would result in a setback greater than the required minimum."
• Front. The district front setback applies, but it "may not preclude the development of an ADU of at least 800 square feet."
• Placement. Detached ADUs go "behind the front facade of the primary unit," unless that would block an 800 square foot ADU.

A non-habitable accessory building follows Section 15-2004 instead. It "may contain a toilet, shower, and sink," but "Bathtubs and stoves are not permitted." An ADU, by contrast, "must have its own entrance and include facilities for daily living including, at minimum, a kitchen, bathroom, and bedroom."

Junior ADUs and Tiny Homes on Wheels

"A JADU shall not be larger than 500 square feet and must be contained entirely within a single-unit primary residence. Attached garages are considered part of a primary residence." It needs its own entrance, a kitchen and a bedroom. It may use an efficiency kitchen, with "a cooking facility with appliances and a food preparation counter and storage cabinets." When it shares a bathroom with the house, it "must include an interior entrance to the main living area that is separate from the main entrance to the JADU."

A tiny house on wheels is a small home built on a trailer frame. Fresno counts one as an ADU "if it meets all the requirements of this section," and adds three conditions, the first being certification to a national (ANSI) building standard: it must be "ANSI certified, be placed on an engineered foundation system, and use skirting to enclose the area between the home and the ground."

Where the City Text Differs From State Law

• Owner on site for a junior ADU. Section 15-2754(F)(1) says "The owner must reside in either the primary residence or in the JADU," with an exception only for a governmental agency, land trust or housing organization. Government Code 66333 says "Owner-occupancy shall not be required if the junior accessory dwelling unit has separate sanitation facilities." The statute controls, and the City's own preemption sentence says so. A junior ADU with its own bathroom needs no owner on site.
• Impact fees on larger ADUs. Footnotes in the 2026 Master Fee Schedule say "ADUs larger than 750 sq. ft. pay the Multi-family residential rate." Government Code 66311.5 says fees on an ADU over 750 square feet "shall be charged proportionately in relation to the square footage of the primary dwelling unit." The statute controls. Ask the City to show the proportional calculation on any ADU fee invoice.

The fee footnotes also disagree with each other. Most say ADUs "less than 750 sq. ft. are not charged Development Impact Fees." The Fire Impact Fee footnote says "less than 70 sq. ft.," and the New Growth Area Major Street footnote says ADUs "larger than 705 sq. ft." pay the multi-family rate. State law sets the line at 750 square feet of interior livable space, with no impact fee at or below it.

Renting and Selling ADUs

Owner-occupancy is not required for a regular ADU: "ADUs. Owner-occupancy is not required." Rentals must be "for terms of 30 consecutive days or longer," which rules out nightly vacation rentals.

Fresno lets an owner sell an ADU apart from the house. Section 15-2754(F)(2) says an ADU "may be sold, or title thereto transferred, separate and apart from the rest of the property" through either "The creation of a common interest development pursuant to Article 39" and Government Code 66342, or "The filing of a Parcel Map pursuant to Article 35." A common interest development is a condominium-style ownership with shared common areas. Under Government Code 66342, no map or condominium plan may be recorded "without each lienholder's consent," and "A lienholder may refuse to give consent." Ask your mortgage lender before you plan a sale.

A junior ADU stays with the house. "JADUs that rely on shared facilities are required to record a deed restriction prohibiting the sale of the JADU separate from the primary residence."

SB 9 Two-Unit Projects in Fresno

The Fresno code has no SB 9 section, and Table 15-902 still marks a duplex with a dash in RS-1 to RS-4. The City applies Government Code 65852.21 through its SB 9 submittal checklist: "IF THE PROJECT IS 'TWO DWELLING UNITS' APPLY FOR A ZONE CLEARANCE AND IN THE PROJECT DESCRIPTION INPUT 'SB 9 TWO DWELLING UNITS'." A project may be "two new primary dwelling units or the addition of one new primary dwelling unit with one existing primary dwelling unit." Where the use table and the statute differ, the statute controls.

Source: City of Fresno SB 9 submittal checklist, Sections A and General Project Requirements; Government Code 65852.21.

The applicant and owner sign a Housing Demolition and Rental Market Affidavit. It states the lot has not had rental housing withdrawn under the Ellis Act, the state law that lets an owner take rental homes off the market, "within 15 years," and that the project will not demolish or alter housing with an affordability covenant, housing under rent control, or "Housing that has been occupied by a tenant in the last three years." If more than 25 percent of the existing exterior structural walls are demolished, the owner also signs that no tenant lived there in the previous three years.

The checklist states the standards the City may apply. It may "impose objective zoning standards, objective subdivision standards, and objective design review standards that do not conflict with SB 9," but may not apply any that "would physically preclude either of the two units from being at least 800 sq. ft. in floor area." No setback is required for an existing structure, and "A local agency may require a setback of up to four feet from the side and rear lot lines." Since the RS districts set larger setbacks (10 feet on the rear in RS-4 and RS-5, for example), the 4-foot ceiling from the statute is the one that applies to an SB 9 home.

On a lot that is split and also gets two homes per lot, state law limits the total. Government Code 65852.21 says the City "shall not be required to permit an accessory dwelling unit or a junior accessory dwelling unit on parcels that use both" the two-unit and the lot split laws. Fresno's ADU section does not address SB 9 lots, so that state limit is the rule to design for. The statute also sets the deadline: the application "shall be considered and approved or denied within 60 days," or "the application shall be deemed approved."

Where to Go Next

Related on VanPlex: the Fresno overview, California ADU law and SB 9 in California.

Frequently Asked Questions

Official sources (checked October 2026)