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Development Services

Residential Building Permits: Group R-2 vs. Group R-3

The purpose of this information bulletin is to explain permitting requirements for residential projects (single- and multi-dwelling unit buildings). Specifically, this Information Bulletin describes the differences between occupancy Groups R-2 and R-3, the two permit types – Building Permit and Combination Building Permit, along with the building code, submittal, and inspection requirements for the different permit types. Congregate occupancies, care facilities and other uses that are not single- or multi-dwelling unit uses are not included in the scope of this Information Bulletin.

I. Definitions

  1. Below are the definitions for the different occupancy groups per the California Building Code (CBC)
  • Dwelling: A building that contains one or two dwelling units used, intended or designed to be used, rented, leased, let or hired out to be occupied for living purposes.
  • Dwelling Unit: A single unit providing complete, independent living facilities for one or more persons, including permanent provisions for living, sleeping, eating, cooking and sanitation.
  • Fire Area: The aggregate floor area enclosed and bounded by fire walls, fire barriers, exterior walls or horizontal assemblies of a building. Areas of the building not provided with surrounding walls shall be included in the fire area if such areas are included within the horizontal projection of the roof or floor above.
  • Group R-2: Residential occupancies containing sleeping units or more than two dwelling units where the occupants are primarily permanent in nature, including apartment houses and other nontransient residential uses.
  • Group R-3: Residential occupancies where the occupants are primarily permanent in nature and not classified as other Group R occupancies that do not contain more than two dwelling units.
  • Sleeping Unit: A single unit that provides rooms or spaces for one or more persons, includes permanent provisions for sleeping and can include provisions for living, eating and either sanitation or kitchen facilities but not both. Such rooms or spaces that are also a part of a dwelling unit are not sleeping units.
  1. Below are the definitions per the San Diego Municipal Code (SDMC) Chapter 11, Article 3, Division 1 and Development Services Department interpretations:
  • Accessory Dwelling Unit (ADU): An attached or detached residential dwelling unit that is 1,200 square feet in size or less, provides complete independent living facilities for one or more persons, including permanent provisions for living, sleeping, eating, cooking, and sanitation, and is located on a lot with a proposed or existing single-dwelling unit or multiple dwelling unit.
  • Detached: Dwellings or dwelling units that do not share any common walls, stairways, decks, roofs or structural members and meet requirements for fire separation distance per the CBC/CRC. Flashing can be provided between detached structures and still be considered detached. Detached dwellings or dwelling units must have exterior wall coverings (weather protection) provided on all sides.
  • Junior Accessory Dwelling Unit (JADU): A dwelling unit or sleeping unit (modified for comparison with the CBC) that is 500 square feet or less in size and is contained entirely within an existing or proposed single-dwelling unit on a residential single-dwelling unit lot. A JADU may include separate sanitation facilities or may share sanitation facilities with the single-dwelling unit.
  • Kitchen: An area used or designed to be used for the preparation of food, which includes facilities to aid in the preparation of food, such as a sink, a refrigerator and stove, a range top or an oven.

II. Permit Types

Per SDMC Section 129.0202 (a), no structure regulated by the Land Development Code shall be erected, constructed, enlarged, altered, repaired, improved, converted, permanently relocated, or partially demolished unless a Building Permit has first been obtained from the Building Official, except as exempted in Sections 129.0202(b) and 129.0203. Depending upon the number of dwelling units in the building and the structure's design, a project will either receive a Combination Building Permit or a Building Permit. See Table 1 below for examples of typical projects and the required permit types.

  1. Combination Building Permit
  1. Applicable Project Types
    A Combination Building Permit is issued for detached one- and two-family dwellings and for townhouses designed per the California Residential Code (CRC). In addition, a Combination Building permit will be issued for an existing two-family dwelling that is converting an existing enclosed garage (not a carport) into a new dwelling unit and not adding any additional fire area. If the structure is attached to any commercial use, such as an office, retail or restaurant space, the project no longer qualifies for a Combination Building Permit and must be issued a Building Permit.
  2. Building Code
    Combination Building Permit projects may be designed in accordance with the CRC and all referenced and applicable standards. However, it is acceptable to design a project receiving a Combination Building Permit to the requirements in the CBC, with the exception of townhouses. A townhouse project wishing to receive a Combination Building Permit must be designed per the CRC (see Technical Bulletin RESD-3-3, Townhouses, for details on how to design a townhouse per the CRC). Note that one- and two-family dwellings that are more than three stories above grade plane must be designed in accordance with the CBC.
  3. Submittal Requirements
    The plan submittal must be in accordance with the Project Submittal Requirements, Section 2A. Note that full Mechanical, Plumbing and Electrical Plans are not required to be submitted; however, California Energy Code documentation is required to be provided. Plans must show all existing, proposed and relocated plumbing fixtures, the location, size, make and model of proposed heating equipment and water heater, and the location of all smoke detectors and carbon monoxide detectors.
  4. Mechanical, Electrical and Plumbing Review and Inspectors
    1. Plan review will not include Mechanical or Electrical Reviewers. Combined Reviewers will perform the review for the residential energy calculations, plumbing fixtures, heating equipment and water heater.
    2. Inspections will be performed by Combination Inspectors only.
  5. Expiration of Permit
    Combination Building Permits expire two years after the date of permit issuance.
  6. Certificate of Occupancy
    A Certificate of Occupancy is not issued for one- and two-family dwelling projects and for townhomes designed per the CRC.
  1. Building Permit
    1. Applicable Project Types
      A Building Permit is issued for all projects not qualifying for a Combination Building Permit.
    2. Building Code
      Projects requiring a Building Permit must be designed in accordance with the CBC and all other applicable California Building Standards.
    3. Submittal Requirements
      The plan submittal must be in accordance with the Project Submittal Requirements, Section 2. Note that full Mechanical, Plumbing and Electrical Plans are required to be submitted.
    4. Mechanical, Electrical and Plumbing Review and Inspectors
      1. Plan review will include Mechanical and Electrical Reviewers. 
      2. Inspections will be performed by Structural, Mechanical, Electrical, and Life Safety Inspectors (as applicable).
    5.  Expiration of Permit
      Building Permits expire four years after the date of permit issuance.
    6. Certificate of Occupancy
      A Certificate of Occupancy is issued for all new projects and any occupancy change.

III. Requirements Based Upon Occupancy Group

Below is a list of some of the major differences between a Group R-2 and R-3 designed structure. Note that this is not a complete list, so verify all requirements in the applicable Codes and standards. See Table 1 below for examples of typical projects and the occupancy groups.

  1. Group R-2 Occupancy
    1. The applicable building code is the CBC.
    2. Accessibility is required based on the number of units contained in the building per CBC Chapter 11A or 11B (for publicly funded projects). Projects containing four or more condominiums or three or more apartments trigger accessibility.
    3. Fire sprinklers are required and must be either an NFPA 13 or NFPA 13R sprinkler system throughout the building. The only exception would be as allowed by Technical Bulletin RESD-3-4 for Accessory Dwelling Units.
    4. A fire alarm system per CBC Section 907 may be required.
  2. Group R-3 Occupancy
    1. R-3 occupancies may be designed per the CBC or CRC.
    2. Accessibility is not required for one- and two-family dwelling projects. Fire sprinklers are required for all new Group R-3 occupancies, except as allowed by Technical Bulletin RESD-3-4 for Accessory Dwelling Units. When required, fire sprinklers shall be in accordance with NFPA 13D or the CRC.

IV. Are ADUs and JADUs Dwelling Units?

  1. ADUs are always dwelling units as they meet the CBC definition of a dwelling unit.
  2. JADUs may or may not be a dwelling unit. To be considered a dwelling unit, the JADU would need to meet all requirements of the definition of a dwelling unit, including a full kitchen and sanitation. A JADU not provided with a full kitchen and/or a full bathroom would be considered a sleeping unit.

Table 1 – Examples of Residential Projects and the Respective Occupancy Classification and Permit Type

Structure Description

Occupancy
Classification

 Permit
Type

New Detached Single Dwelling Unit

R-3

Combination Permit

New Detached ADU

R-3

Combination Permit

New Detached Duplex Structure (Two Dwelling Units in One Detached Structure)

R-3

Combination Permit

New Townhouses Designed per CRC

R-3

Combination Permit

New ADU Attached to Existing Single-Dwelling Unit

R-3

Combination Permit

New JADU Attached to Existing Single-Dwelling Unit

R-3

Combination Permit

New ADU and New JADU (not a dwelling unit) Attached to an Existing Single-Dwelling Unit

R-3

Combination Permit

New JADU (not a dwelling unit) Attached to Existing Duplex

R-3

Combination Permit

Garage Conversion to a New ADU Attached to an Existing Single-Dwelling Unit

R-3

Combination Permit

Detached Garage Converted to ADU

R-3

Combination Permit

Detached Garage Converted to Two ADUs or Two ADUs and a JADU (not a dwelling unit)

R-3

Combination Permit

Existing Single-Dwelling Unit Converted to Two ADUs or Dwelling Units

R-3

Combination Permit

Attached Garage Conversion to a New ADU (no additional area added)
Attached to an Existing Duplex

R-2

Combination Permit

New ADU and New JADU (a dwelling unit) Attached to an Existing Single-Dwelling Unit

R-2

Building Permit

Carport Converted to an ADU attached to a Duplex

R-2

Building Permit

New ADU Attached to Existing Duplex

R-2

Building Permit

New JADU (a dwelling unit) Attached to Existing Duplex

R-2

Building Permit

New ADU and New JADU (not a dwelling unit) Attached to an Existing Duplex

R-2

Building Permit

New ADU and New JADU (a dwelling unit) Attached to an Existing Duplex

R-2

Building Permit

New Three or More Attached Dwelling Units

R-2

Building Permit

New ADU or JADU Attached to Existing Building with Three or More Attached-Dwelling Units

R-2

Building Permit

Detached Garage Converted to 3 or more ADUs or Dwelling Units

R-2

Building Permit

Existing Single Dwelling Unit Conversion to Three or More ADUs or Dwelling Units

R-2

Building Permit

References