Urban Dwellings (SB-9)
An urban dwelling is a second primary residential dwelling allowed on a parcel with an existing single-family dwelling in eligible areas as authorized by the County Code. An urban dwelling is considered a primary use on a residential parcel.
To apply for urban dwelling, complete the Urban Dwelling Pre-Screening Checklist and then the Building (Construction) Permit Application process.
**The regulations outlined in the Urban Dwelling Pre-Screening Checklist may impact the allowed number of dwellings and site design.**
Updated Regulations
On June 3, 2025, the Board of Supervisors adopted updated regulations relating to urban dwellings (Ordinance 3537), which take effect July 3, 2025.
Updated regulations include:
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Urban Dwellings Pre-Screening Checklist. An urban dwelling application is required to include a checklist certifying the proposed project complies with regulations that may impact the allowed number of dwellings and site design.
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Site layout plan. An urban dwelling application is required to include a site layout plan, including existing or anticipated single-family dwellings, urban dwellings, accessory dwellings, and urban lot splits.
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Eligible areas. Eligible areas include urban areas and urban clusters as designated by either the 2010 or 2020 census data or areas within a County Urban Reserve Line, not including exclusion areas defined in State Law.
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Size. The maximum floor area for an urban dwelling is 1,200 square feet.
Last updated: June 20, 2025
FAQs
Inland Area of Unincorporated County
- SB-9 regulations go into effect starting January 1, 2022.
Coastal Zone of Unincorporated County
- Since SB-9 does not supersede and cannot in any way alter or lessen the effect or application of the California Coastal Act of 1976, the County is working with California Coastal Commission staff to determine the applicability of SB-9 in the Coastal Zone, as it relates to the County's Local Coastal Program (LCP).
- According to initial direction from California Coastal Commission staff, all approvals relating to SB-9 must also be consistent with the LCP. Since the main components of SB-9 largely conflict with the current LCP, an application for construction and/or subdivision solely based on SB-9 cannot be approved in the Coastal Zone. As such, unless it is demonstrated that an applicant is consistent with both SB-9 and the current LCP or until the LCP is amended in accordance with SB-9, the County is not accepting applications for construction and/or subdivision solely based on SB-9 at this time in the Coastal Zone.
Eligible Lots: Please follow the below steps to find out if a lot is eligible
- Open Land Use View
- The “Senate Bill 9 Eligible Parcels” layer is turned on by default. To see other layer options, switch from the "Home" panel to the "Layers" panel in the bottom left corner.
- Search for the lot with the Assessor's Parcel Number (APN) or address (Tip: search bar is found on the top right corner)
Eligibility Requirements: A lot is considered an "eligible lot" if it satisfies all of the below requirements
- The lot is located wholly within an urbanized area or urban cluster, as designated by the United States Census Bureau;
- The lot has a land use category designation of Residential Single-Family (RSF), Residential Rural (RR), or Residential Suburban (RS);
- The lot is not located within the exclusion areas, as described in Government Code § 65913.4(a)(6)(B)-(K):
(B) Either prime farmland or farmland of statewide importance,
(C) Wetlands
(D) Within a very high fire hazard severity zone
(E) A hazardous waste site
(F) Within a delineated earthquake fault zone
(G) Within a special flood hazard area
(H) Within a regulatory floodway as determined by the Federal Emergency Management Agency
(I) Lands identified for conservation
(J) Habitat for protected species
(K) Lands under conservation easement
Subdivision Component (Urban Lot Split) Only: A lot that has been established through a lot split, as allowed under SB-9 or any of the corresponding Government Code sections, shall no longer be eligible for the subdivision component.
Demolition or Alteration of Existing Housing is Prohibited in the Following Circumstances:
- Housing that is subject to a recorded covenant, ordinance, or law that restricts rents to levels affordable to persons and families of moderate, low, or very low income;
- Housing that is subject to any form of rent or price control through a public entity’s valid exercise of its police power;
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Housing that has been occupied by a tenant in the last three years.
Demolition or Alteration of Existing Housing is Permitted in the Following Circumstances:
- Demolition does not involve more than 25% of the existing exterior structural walls;
- The site has not been occupied by a tenant in the last three years.
Development Standards for Primary Dwellings:
- Setbacks
- Front: Subject to applicable land use standards
- Side: 4 feet minimum
- Rear: 4 feet minimum
- Interior: Subject to applicable land use standards
- Exception: The setbacks of an existing permitted structure may be maintained for [a] the conversion of an existing permitted structure to a primary dwelling, or [b] the construction of a primary dwelling within the same footprint of an existing permitted structure.
- Parking: Minimum of 1 off-street parking space per primary dwelling.
- Except as provided above, both primary dwellings are subject to all other applicable land use standards (height, size, etc.).
- Compliance with Local Agency Management Program (LAMP) develops minimum standards for the treatment and disposal of sewage through onsite wastewater treatment systems. Local Agency Management Program (LAMP) - County of San Luis Obispo.
Rental Limitation:
- Rental of both primary dwellings shall be for terms longer than 30 days (vacation rental, bed & breakfast, and homestays are prohibited for both primary dwellings).
Demolition or Alteration of Existing Housing: Demolition or alteration of the below types of housing is prohibited
- Housing that is subject to a recorded covenant, ordinance, or law that restricts rents to levels affordable to persons and families of moderate, low, or very low income;
- Housing that is subject to any form of rent or price control through a public entity's valid exercise of its police power;
- Housing that has been occupied by a tenant in the last three years.
Design Standards for New Lots
- Maximum Number of Lots: 2 lots
- Minimum Lot Size: 1,200 square feet and no smaller than 40% of original lot size
- Access: Both lots shall have access to, provide access to, or adjoin the public right-of-way
- Public Services and Facilities: Easements for the provision of public services and facilities may be required
- Compliance with Local Agency Management Program (LAMP) develops minimum standards for the treatment and disposal of sewage through onsite wastewater treatment systems. Local Agency Management Program (LAMP) - County of San Luis Obispo.
Limitation on Use: Both lots shall be limited to residential uses
Rental Limitation: Rental of both primary dwellings shall be for terms longer than 30 days (vacation rental, bed & breakfast, and homestays are prohibited for both primary dwellings)
Requirement of Owner-Occupancy: The property owner shall sign an affidavit stating they intend to occupy one of the primary dwellings on one of the resulting parcels as their principal residence (1) for a minimum of three years from the final parcel map recordation date for the urban lot split or (2) for a minimum of three years from the date the first dwelling unit permit is finaled if there are no existing residences at the time of final parcel map recordation, unless the owner is a community land trust or qualified non-profit corporation.