San Bernardino | ADUs and SB 9

San Bernardino, California ADUs and SB 9: ADU Sizes, Heights and Setbacks, Parking, Junior ADUs, Fees, Pre-Approved Plans and Two-Unit Projects

An accessory dwelling unit (ADU) is a second home on a lot that already has, or will have, a main home. A junior ADU (JADU) is a unit of no more than 500 square feet inside a house. The City of San Bernardino keeps its ADU rules in Section 19.04.030(2)(P) of the Development Code and has amended that section four times since adopting it in 2021. The latest version is Exhibit A of Ordinance No. MC-1659, adopted on February 4, 2026. This page covers that ordinance, the City's SB 9 section for two-unit projects, the fees, and the places where the City text and state law differ. The San Bernardino overview has the summary.

Which Text Is in Force

Read the ordinance before the City's posted code. The Council minutes of February 4, 2026 record the result as "ADOPTED ORDINANCE NO. MC-1659 [6-0]." The ordinance says the ADU section "is hereby amended and restated to read in its entirety as provided in Exhibit A," and "This Ordinance takes effect thirty (30) days after its adoption." Thirty days after February 4, 2026 is March 6, 2026 (VanPlex arithmetic).

The Residential Zones chapter on the City's Development Code page prints "Feb. 2025" on every page, and its ADU section ends its history note at Ordinance MC-1645 of January 15, 2025. The City's ADU page links to that chapter. So the posted chapter is one version behind. The staff report for the adoption lists the history:

• May 5, 2021. The Council "adopted Ordinance No. MC-1559, establishing standards for the development of Accessory Dwelling Units."
• December 7, 2022. An urgency ordinance "updated the verbiage regarding ADU's on multi-family lots and established standards for units of certain sizes."
• January 15, 2025. Ordinance No. MC-1645 "streamlined the application process, updated definitions, expanded the prohibition on replacement parking and increased the allowable number of detached accessory dwelling units on a multi-family lot."
• December 3, 2025. The Council adopted Urgency Ordinance No. MC-1658U, "which became effective immediately and granted City staff additional time to be compliant with recent State law (AB 462, AB 1154 and SB 543)."
• February 4, 2026. The Council adopted MC-1659 on second reading. The Planning Commission had recommended it on December 9, 2025.

ADU Types and Limits

Source: City of San Bernardino, Ordinance No. MC-1659, Exhibit A, subsections 3, 5, 6.b and 7, adopted February 4, 2026.

The ordinance sorts every unit into one of two classes. "Class 1 ADUs and JADUs are approved under Government Code section 66323," the state list of units a city must approve. "Class 2 ADUs are approved under Government Code sections 66314-66322," where a city may set its own standards within limits. The state rules are on the California ADU law page.

• Where. A Class 1 ADU "may be created on a lot in a residential or mixed-use zone." A Class 2 ADU may be created "on a lot that is zoned to allow single-family dwelling residential use or multifamily dwelling residential use." A junior ADU "may only be created on a lot zoned for single-family residences."
• Three on a house lot. "An ADU and JADU approved under subsection 5.a.i may be combined with an ADU approved under subsection 5.a.ii." Those are the converted ADU, the junior ADU and the detached ADU of up to 800 square feet.
• Density. A conforming ADU or junior ADU will not be "Deemed to exceed the allowable density for the lot on which the ADU or JADU is located."
• The 800 square foot guarantee. No size percentage, floor area ratio, front setback, lot coverage limit or open-space rule "may require the ADU have less than 800 square feet of interior livable space."

Class 2 Standards: Size, Yards, Coverage and Height

These apply only to Class 2 ADUs, the ones that are larger or placed differently than the Class 1 units.

• Size. "850 square feet of interior livable space for a studio or one-bedroom unit and 1,000 square feet of interior livable space for a unit with two or more bedrooms."
• Attached ADUs. "An attached ADU that is created on a lot with an existing primary dwelling is further limited to 50 percent of the floor area of the existing primary dwelling."
• Floor area ratio. "No ADU subject to this subsection 7 may cause the total FAR of the lot to exceed 45 percent." Floor area ratio, or FAR, is building floor area divided by lot area.
• Lot coverage and open space. The ADU may not "cause the total lot coverage of the lot to exceed 50 percent" or "cause the total percentage of open space of the lot to fall below 50 percent."
• Setbacks. "ADUs that are subject to this subsection 7 must conform to 4-foot side and rear setbacks" and "to 25-foot front setbacks." No setback is required where the ADU "is constructed in the same location and to the same dimensions as an existing structure."
• Stories. A detached Class 2 ADU may not "have more than one story." An attached one "may not exceed two stories."
• How height is measured. "height is measured from existing legal grade or the level of the lowest floor, whichever is lower, to the peak of the structure."
• Room shape. "The interior horizontal dimensions of an ADU must be at least 10 feet wide in every direction, with a minimum interior wall height of seven feet."

Class 2 Standards: Parking, Design and Landscaping

• Parking. "One off-street parking space is required for each ADU or bedroom, whichever is less. The parking space may be provided in setback areas or as tandem parking." Tandem parking means cars lined up one behind another.
• Six exceptions. No space is required where the ADU "is located within one-half mile walking distance of public transit," is in "an architecturally and historically significant historic district," "is part of the proposed or existing primary residence or an accessory structure," where street parking permits are required and not offered to the occupant, where a car share stop is within one block, or where the ADU is filed with a new house or apartment building that meets one of the other five.
• Public transit. The ordinance defines it as "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." A bus stop meets that wording.
• No replacement. When a garage, carport or parking space "is demolished in conjunction with the construction of an ADU or converted to an ADU, those off-street parking spaces are not required to be replaced."
• Matching the house. "The materials and colors of the exterior walls, roof, and windows and doors must be the same as those of the primary dwelling," and "The roof slope must match that of the dominant roof slope of the primary dwelling."
• Privacy. "No window or door of the ADU may have a direct line of sight to an adjoining residential property." Windows and doors less than 30 feet from a property line that is not a street line must be high windows "with the bottom of the glass at least six feet above the finished floor," or use frosted or obscure glass.
• Screening plants. "At least one 15-gallon size plant must be provided for every five linear feet of exterior ADU wall," planted at least six feet tall, or "a solid fence of at least six feet in height may be installed." Plants must be drought-tolerant and "from the city's approved plant list."
• Near historic property. "An ADU that is on or within 600 feet of real property that is listed in the California Register of Historic Resources must be located so as to not be visible from any public right-of-way."
• An ADU that falls short of a standard. Subsection 10 says an ADU that does not meet the objective standards "may be allowed by the city with a conditional use permit," which is a hearing process.

Rules for Every ADU and Junior ADU

• Sprinklers. "Fire sprinklers are required in an ADU or JADU if sprinklers are required in the primary residence," and building one "does not trigger a requirement for fire sprinklers to be installed in the existing primary dwelling."
• Rentals. "No ADU or JADU may be rented for a term that is shorter than 30 days. This prohibition applies regardless of when the ADU or JADU was created."
• Separate sale. An ADU may be rented, and may be sold apart from the main home only as Government Code 66341 allows.
• Septic systems. An owner on an onsite wastewater system must include "a percolation test completed within the last five years or, if the percolation test has been recertified, within the last 10 years."
• Owner occupancy. "ADUs are not subject to an owner-occupancy requirement." For a junior ADU the owner "must reside on the property, in either the primary dwelling or JADU," unless "The JADU has separate sanitation facilities" or a governmental agency, land trust or housing organization owns the property.
• Junior ADU deed restriction. "Prior to issuance of a certificate of occupancy for an JADU, a deed restriction must be recorded against the title of the property in the County Recorder's office." It says the junior ADU "may not be sold separately from the primary dwelling."
• Junior ADU layout. A junior ADU "is contained entirely within an existing or proposed single-family structure," and an attached garage counts as part of the house. It has an efficiency kitchen with "A cooking facility with appliances" and a counter and cabinets. Without its own bathroom it needs an inside door to the house as well as its own outside door.
• Existing violations. "The city will not deny an ADU or JADU application due to a nonconforming zoning condition, building code violation, or unpermitted structure on the lot that does not present a threat to the public health and safety and that is not affected by the construction of the ADU or JADU."
• Unpermitted ADUs built before 2020. The City "may not deny a permit to legalize an existing but unpermitted ADU or JADU that was constructed before January 1, 2020" for breaking building standards or the ADU rules, unless a correction is needed under the state substandard building law.
• Occupancy timing. "No certificate of occupancy for an ADU or JADU may be issued before the certificate of occupancy is issued for the primary dwelling unit," with an exception after a state-declared emergency.

The ADU Permit, Step by Step

"Every ADU and JADU requires an ADU permit and a building permit." Both are ministerial, which means staff check the plans against fixed rules: "Ministerial permits for an ADU or JADU are considered and approved without discretionary review or a hearing."

• Completeness. The City "will determine whether an application to create or serve an ADU or JADU is complete and will provide written notice of the determination to the applicant within 15 business days." A notice of incompleteness "must list the incomplete items," and on a second submittal "The city may not require the application to include an item that was not included in the original notice."
• Decision. "The city must approve or deny an application to create an ADU or JADU within 60 days from the date that the city receives a complete application. If the city has not approved or denied the complete application within 60 days, the application is deemed approved," unless the applicant asks for a delay or the ADU is filed with a new house.
• Denial. A denial comes with "a list of all the defective or deficient items and a description of how the application may be remedied."
• Appeal. The applicant may appeal an incompleteness finding or a denial in writing to the city clerk. "The planning commission will review the written appeal" and give "a final written determination to the applicant within 60 business days after receipt of the appeal."
• Garage demolition. "A demolition permit for a detached garage that is to be replaced with an ADU is reviewed with the application for the ADU and issued at the same time."

The City's Accessory Dwelling Units page describes the steps at the permit counter.

• Plans. An owner may hire a designer or use the "Pre-Selected ADU Plans Program." The page lists two detached plans, "462 sq ft (1 bedroom / 1 bathroom)" and "738 sq ft (2 bedrooms / 2 bathrooms)," and says "The City of San Bernardino does not have rights to the plans; designers must be contacted directly for the purchase of plans."
• Planning first. Plans go to the Planning Division for pre-approval. The page gives the Planning number as 909-998-2300.
• Building and Safety. The owner then submits three sets of 24 by 36 inch plans, calculations and a building application. "Photovoltaic is not allowed to be deferred and must be included in the completed plan set." Photovoltaic means solar panels.
• Other clearances. San Bernardino County Fire, the City Water Department for a "Sewer Capacity/Will Serve Letter," the Land Development Division, and Real Property for the new address.
• Review time. "1st submittal plan reviews are subjected to 15-20 business days. 2nd and subsequent reviews are 10 to 15 business days."
• Site conditions. The page warns that "the city does have high wind areas, high seismic areas and high fire severity areas, this may affect construction costs and construction limitations."

ADU Fees

• Impact fees. An impact fee is a charge on new building that pays for public facilities. "No impact fee is required for a JADU or for an ADU that has less than 750 square feet of interior livable space." A larger ADU is charged "proportionately in relation to the square footage of the primary dwelling unit." The ordinance gives the formula: "the floor area of the ADU, divided by the floor area of the primary dwelling, times the typical fee amount charged for a new dwelling."
• An example. A 900 square foot ADU behind an 1,800 square foot house pays half of each fee (VanPlex arithmetic: 900 divided by 1,800). The Land Development impact fee schedule, dated February 15, 2022 and updated each July 15, lists the per-home amounts, which are on the permits and fees page.
• School fees. The ordinance says an ADU or junior ADU "with less than 500 square feet of interior livable space" is not subject to school fees. The City page says "A school fee letter is required for structures 501 sq ft of larger," and that the school district decides.
• Utility connections. A converted ADU or junior ADU on a house lot needs no new or separate utility connection and pays no connection fee or capacity charge. Other ADUs "require a new, separate utility connection directly between the ADU and the utility for any utility that is provided by the city," with a charge "proportionate to the burden created by the ADU."
• ADU permit fee. "The city may charge a fee to reimburse it for costs incurred in processing ADU permits," set by resolution. The Planning, Building and Safety and Public Works fee schedules the City posts have no line that names an ADU permit, so ask the Planning Division for the amount.

SB 9 Two-Unit Projects

SB 9 is the 2021 state law that makes a city approve two main homes on a lot in a single-family zone with no hearing. The two-unit rule is Government Code 65852.21. San Bernardino's version is Section 19.04.030(2)(X), added by Ordinance MC-1570U, which the code dates 1/9/22. The posted text carries no later amendment note.

Source: San Bernardino Development Code, Section 19.04.030(2)(X), subsections 3 and 5 (pages dated Feb. 2025).

• What it is. "A 'two-unit project' means the development of two primary dwelling units or, if there is already a primary dwelling unit on the lot, the development of a second primary dwelling unit on a legally subdivided lot."
• Size. "The total floor area of each primary dwelling built that is developed under this section must be (I) less than or equal to 800 and (II) more than 500 square feet." An existing house larger than 800 square feet "may not be expanded."
• Height. "On a lot that is larger than 2,000 square feet, no new primary dwelling unit may exceed a single story or 16 feet in height, measured from grade to peak of the structure." No rooftop deck is permitted.
• With ADUs. "A lot that is not created by an urban lot split may have a two-unit project under this subpart (X), plus any ADU or JADU that must be allowed under state law and the City's ADU ordinance."
• Design. A new home must match the existing one "in exterior materials, color, and dominant roof pitch." Windows and doors may not have "a direct line of sight to an adjoining residential property," and evergreen screening or a six-foot solid fence is required toward adjacent lots.
• Utilities. "Each primary dwelling unit on the lot must have its own direct utility connection to the utility service provider."
• The rest of the lot. "A project under this section is a change of use and subjects the whole of the lot, and all structures, to the city's current code," and "A two-unit project may only be approved if all nonconforming zoning conditions are corrected."
• Fire zones. In a very high fire hazard severity zone the lot needs access to a paved street at least 40 feet wide with two independent points of access, sprinklers in all enclosed structures, and "a water reservoir of at least 5,000 gallons per dwelling" where there is no swimming pool.
• Deed restriction. The owner records one that bars short rentals, non-residential use and separate sale of the homes, and "Expressly requires the individual property owners to live in one of the dwelling units on the lot as the owners' primary residence and legal domicile."

The lot split half of SB 9 is on the lot size and subdivisions page.

Where the City Text, City Documents and State Law Differ

A city ADU or SB 9 rule that is stricter than the statute has no force to that extent. These are the differences found.

• The posted code against the ordinance. The posted chapter has no floor area ratio or open space rule for ADUs, requires a deed restriction for every ADU "Prior to issuance of a building permit," and says the ADU entrance must be "on the side or rear building façade, not facing a public-right-of-way." Ordinance MC-1659 dropped the entrance rule, kept the deed restriction for junior ADUs only, and added the 45 percent FAR and 50 percent open space limits. The ordinance controls.
• The 750 square foot limit. The ordinance exempts an ADU with "less than 750 square feet." Government Code 66311.5 bars impact fees on an ADU "that has 750 square feet of interior livable space or less." The City's impact fee schedule charges an ADU "that is 750 square feet or larger." An ADU of exactly 750 square feet is exempt under the statute.
• SB 9 standards that apply only to SB 9. Since amendments that followed the City section, Government Code 65852.21 says a city "shall not impose objective zoning standards, objective subdivision standards, and objective design standards that do not apply uniformly to development within the underlying zone." The City caps an SB 9 home at 800 square feet and 16 feet. In the RS zone itself the code asks a house for at least 1,200 square feet and allows 2.5 stories and 35 feet.
• SB 9 owner occupancy. The City requires the owners of a two-unit project to live on the lot. Government Code 65852.21 lists the conditions a city may add, which are objective standards, parking and a percolation test, and owner occupancy is absent from the list.
• SB 9 deadline. The statute says a two-unit application "shall be considered and approved or denied within 60 days," and is deemed approved after that. The City section has no decision deadline.
• SB 9 reasons to deny. The City section allows denial for an impact "on either public health and safety or on the physical environment." The statute now names only an impact "upon public health and safety."
• The demolition cap. The City section says a project "may not involve the demolition of more than 25 percent of the existing exterior walls of an existing dwelling unless the site has not been occupied by a tenant in the last three years." The statute as it reads today limits demolition and alteration only for three kinds of protected housing.
• A copying error. The deed restriction list for a two-unit project includes a line that says the property "is formed by an urban lot split," which fits the lot split section it was copied from.

Ask the Planning Division in writing which SB 9 size, height and owner-occupancy rules it applies today.

Recent Council Items

• August 20, 2025. The Council agenda carried a "Discussion on Accessory Dwelling Units (ADUs) and Research on Limits within State Law," placed by a council member.
• December 3, 2025. The agenda listed Urgency Ordinance No. MC-1658U, the "Accessory Dwelling Unit 2025 Legislative Update."
• June 17, 2026. The minutes record that the Council "APPROVED MOTION TO DENY ORDINANCE NO. MC-1661," which would have prohibited short-term and vacation rentals in the city, by a 4-3 vote. The 30-day rental rules for ADUs and SB 9 homes above are in separate sections and still apply.

Limits of This Page

The ADU rules come from the ordinance exhibit in the Council packet of February 4, 2026, and the vote from the minutes. The signed copy of the ordinance and the text of Urgency Ordinance MC-1658U were not read. City Council agendas through October 7, 2026 and Planning Commission agendas through September 8, 2026 list no later ADU or SB 9 ordinance. The City's ADU permit application, its approved plant list, the junior ADU deed restriction form and the SB 9 application forms were not read. Building permit fees depend on the project, and school fees and water and sewer charges come from other agencies. Whether a lot is within one-half mile walking distance of transit depends on its location. Land outside the city limits follows San Bernardino County's rules.

Where to Go Next

Related on VanPlex: the San Bernardino overview, the California ADU law page and the California SB 9 page.

Frequently Asked Questions

Official sources (checked October 2026)