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Lot splits under SB 9 in Brisbane

Brisbane's own rules on lot splits under sb 9, with the code text for every value, and the state law underneath.

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Each rule below links to the section of the Brisbane Municipal Code it was read from, with the code text one click away (checked October 2026). General information, not legal advice.

What Brisbane's code says

Brisbane code What Brisbane's code adds
How the lot may be divided
  • At most 2 lots of about equal area; neither may be smaller than 40% of the original lot.
    Applies: Urban lot split.
    § 17.05.080 · code text
    The parcel map subdivides an existing lot of record to create no more than two (2) legal lots of record of approximately equal lot area provided that one lot shall not be smaller than forty (40) percent of the lot area of the original lot of record proposed for subdivision.
Minimum new lot size
  • Each new lot must be at least 1,200 square feet.
    Applies: Both newly created lots.
    § 17.05.080 · code text
    Both newly created lots of record shall be no smaller than one thousand two hundred (1,200) square feet.
Setbacks
  • At least 4 feet.
    Applies: Side and rear setbacks for primary units in a two-unit development without a lot split; a smaller district setback applies where allowed.
    § 17.05.070 · code text
    Minimum side and rear setbacks for the primary dwelling units shall be four (4) feet, except for the following:
  • No setback required.
    Applies: An existing legal non-conforming structure, or a replacement built in the same place with the same dimensions.
    § 17.05.070 · code text
    No setback shall be required for an existing legal non-conforming structure, or a replacement structure constructed in the same location and to the same dimensions as an existing legal non-conforming structure.
Standards
  • The zone's minimum lot width and depth do not apply.
    Applies: Urban lot split.
    § 17.05.080 · code text
    The zoning district lot width and depth dimension minimums shall not apply.
  • Flag lots allowed; flagpole at least 12 feet wide for a driveway unless the city engineer approves less.
    Applies: Urban lot split.
    § 17.05.080 · code text
    The flagpole portion, whether part of the flag lot or an easement on the flag lot, shall have a minimum width of twelve (12) feet to accommodate a driveway, unless a lesser width is approved by the city engineer.
  • No more than 4 dwelling units.
    Applies: On the lot area that would otherwise hold one single-family home, after an urban lot split.
    § 17.05.080 · code text
    With an urban lot split, development of no more than four (4) dwelling units may be built in the same lot area that would otherwise be used for a single-family residence, as shown in Tables a and b provided below.
  • Primary units may be at least 800 square feet despite coverage and FAR limits; above that, zoning floor-area rules apply.
    Applies: Primary units after an urban lot split.
    § 17.05.080 · code text
    Each of the primary dwelling units shall be permitted to be at least eight hundred (800) square feet in floor area, regardless of the zoning district's lot coverage and floor area ratio (FAR) limits.
  • At most 25 feet high for any part of the building between the 4-foot setback and the district setback.
    Applies: Two-unit development where a primary unit uses the 4-foot side or rear setback.
    § 17.05.070 · code text
    no portion of the building that is located in the area between the four-foot setback and the district's setback minimum shall exceed twenty-five (25) feet in height.
  • Primary units may be no more than 25 feet high.
    Applies: Two-unit development on a ridgeline lot in the R-BA district, unless approved by design review.
    § 17.05.070 · code text
    The maximum height of any primary dwelling unit on a ridgeline lot within the R-BA district, as defined in Section 17.02.695, shall be twenty-five (25) feet, except for (i) an existing legal non-conforming structure, (ii) a replacement structure constructed in the same location and to the same dimensions as an existing legal non-conforming structure, or (iii) as approved by design review permit per Section 17.12.040(L).
Owner occupancy
  • Owner or immediate family must live in one unit as a principal residence for at least 3 years.
    Applies: Urban lot split; the owner signs an affidavit before the split is recorded.
    § 17.05.040 · code text
    For urban lot splits, prior to a lot split being recorded, the property owner(s) shall sign an affidavit stating that the owner, or a member or members of the owner's immediate family, intends to occupy one of the dwelling units as the person's principal residence for a minimum of three (3) years.
  • The owner-occupancy rule does not apply.
    Applies: The applicant is a community land trust or a qualified nonprofit corporation.
    § 17.05.040 · code text
    This requirement shall not apply to an applicant that is a "community land trust," as defined in clause (ii) of subparagraph (C) of paragraph (11) of subdivision (a) of Section 402.1 of the Revenue and Taxation Code, or is a "qualified nonprofit corporation" as described in Section 214.15 of the Revenue and Taxation Code.
Parking
  • At least 1 standard off-street parking space, uncovered or carport.
    Applies: Each primary dwelling unit, as the general rule.
    § 17.05.070 · code text
    A minimum of one standard size, off-street parking space (uncovered or carport) for each primary dwelling unit shall be required (refer to Chapter 17.34 for parking space design standards).
  • No off-street parking required.
    Applies: Lot within a half-mile walk of a stop in a high-quality transit corridor or a major transit stop.
    § 17.05.070 · code text
    The lot is located within one-half-mile walking distance of either a transit stop located in a high-quality transit corridor, as defined in Public Resources Code Section 21155(b), or a major transit stop, as defined in Public Resources Code Section 21064.3;
  • No off-street parking required.
    Applies: A designated parking area for one or more car-share vehicles is within 1 block of the lot.
    § 17.05.070 · code text
    There is a designated parking area for one or more car-share facilities within one block of the lot.

Who this affects

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Frequently asked questions

Can I split my lot under SB 9 in Brisbane?

Brisbane's code: At most 2 lots of about equal area; neither may be smaller than 40% of the original lot. (Urban lot split.) (§ 17.05.080); Each new lot must be at least 1,200 square feet. (Both newly created lots.) (§ 17.05.080).

General information, not legal advice.

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