Chapter 3 — OCCUPANCY CLASSIFICATION AND USE
Section 310 — RESIDENTIAL GROUP R
2025 California Building Code (Title 24, Part 2) · 2025 edition · updated 2026-07-27 · California
Italicized text is a California amendment to the model code, as printed in the official publication.
310.1 Residential Group R. ¶
Residential Group R includes, among others, the use of a building or structure, or a portion thereof, for sleeping purposes when not classified as an Institutional Group I or when not regulated by the California Residential Code . Group R occupancies not constructed in accordance with the California Residential Code as permitted by Sections 310.4.1 and 310.4.2 shall comply with Section 420.
310.2 Residential Group R-1. ¶
Residential Group R-1 occupancies containing sleeping units or more than two dwelling units where the occupants are primarily transient in nature, including:
Boarding houses (transient) with more than 10 occupants
Congregate residences (transient) with more than 10 occupants
Hotels (transient)
Motels (transient)
[HCD 1] Efficiency dwelling units (transient)
310.3 Residential Group R-2. ¶
Residential Group R-2 occupancies containing sleeping units or more than two dwelling units where the occupants are primarily permanent in nature, including:
Apartment houses
Large family child care
Small family child care
Congregate living facilities (nontransient) with more than 16 occupants
Boarding houses (nontransient)
Convents
Dormitories
Emergency services living quarters
Fraternities and sororities
Monasteries
Hotels (nontransient)
Live/work units
Motels (nontransient)
Vacation timeshare properties
[HCD 1] Efficiency dwelling units (transient)
310.3.1 Residential Group R-2.1. Residential Group R-2.1 occupancies shall include buildings, structures or parts thereof housing clients, on a 24-hour basis, who because of age, mental disability or other reasons, live in a supervised residential environment that provides personal care services.
This occupancy may contain more than six nonambulatory and/or bedridden clients. (See Section 435 Special Provisions for Licensed 24-Hour Care Facilities in a Group R-2.1, R-3.1 or R-4 Occupancy). This group shall include, but not be limited to, the following:
Assisted living facilities such as: Residential care facilities, Residential care facilities for the elderly (RCFEs), Adult residential facilities, Congregate living health facilities, Group homes, Residential care facilities for the chronically ill, Congregate living health facilities for the terminally ill.
Social rehabilitation facilities such as: Halfway houses, Community correctional centers, Community treatment programs, Work furlough programs, Alcoholism or drug abuse recovery or treatment facilities.
310.3.2 Residential Group R-2.2 (CDCR Only). Residential occupancies operated by CDCR in a community located facility that provides housing and community-based program services for nontransient ambulatory participants in a nonlicensed facility with 24/7 supervision.
310.4 Residential Group R-3. ¶
Residential Group R-3 occupancies where the occupants are primarily permanent in nature and not classified as Group R-1, R-2.1, R-2.2, R-3.1, R-4 or I, including:
Buildings that do not contain more than two dwelling units
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
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OCCUPANCY CLASSIFICATION AND USE
Care facilities that provide accommodations for five or fewer persons receiving care
Congregate residences (nontransient) with 16 or fewer occupants
Boarding houses (nontransient)
Convents
Dormitories
Emergency services living quarters
Fraternities and sororities
Monasteries
Congregate residences (transient) with 10 or fewer occupants
[HCD 1] Efficiency dwelling units
Boarding houses (transient)
Adult care facilities that provide accommodations for six or fewer clients of any age for less than 24 hours
Licensing categories that may use this classification include Adult Day Programs
Alcoholism or drug abuse recovery homes (ambulatory only)
Child-care facilities that provide accommodations for six or fewer clients of any age for less than 24 hours
Licensing categories that may use this classification include, but are not limited to:
Day-Care Center for Mildly Ill Children, Infant Care Center, School Age Child Day-Care Center
Family Day-Care Homes that provide accommodations for 14 or fewer children, in the provider’s own home for less than 24-hours
Adult care and child-care facilities that are within a single family home are permitted to comply with the California Residential Code
Lodging houses with five or fewer guest rooms
310.4.1 Residential Group R-3.1. This occupancy group may include facilities licensed by a governmental agency for a residentially based 24-hour care facility providing accommodations for six or fewer clients of any age. Clients may be classified as ambulatory, nonambulatory or bedridden. A Group R-3.1 occupancy shall meet the requirements for construction as defined for Group R-3, except as otherwise provided for in Section 435 Special Provisions For Licensed 24-Hour Care Facilities in a Group R-2.1, R-3.1 or R-4 Occu- pancy. This group may include:
Adult residential facilities
Congregate living health facilities
Intermediate care facilities for the developmentally disabled habilitative
Intermediate care facilities for the developmentally disabled nursing
Nurseries for the full-time care of children under the age of six, but not including “infants” as defined in Chapter 2
Residential care facilities for the elderly
Small family homes and residential care facilities for the chronically ill
Exception: Group Homes licensed by the Department of Social Services which provide nonmedical board, room and care for six or fewer ambulatory children or children two years of age or younger, and which do not have any nonambulatory clients shall not be subject to regulations found in Section 435.
Pursuant to Health and Safety Code Section 13143 with respect to these exempted facilities, no city, county or public district shall adopt or enforce any requirement for the prevention of fire or for the protection of life and property against fire and panic unless the requirement would be applicable to a structure regardless of the special occupancy. Nothing shall restrict the application of state or local housing standards to such facilities if the standards are applicable to residential occupancies and are not based on the use of the structure as a facility for ambulatory children. For the purpose of this exception, ambulatory children do not include relatives of the licensee or the licensee’s spouse.
310.4.2 Lodging houses. Owner-occupied lodging houses with five or fewer guest rooms shall be constructed in accordance with this code or the California Residential Code, provided that facilities constructed using the California Residential Code are protected by an automatic sprinkler system installed in accordance with Section 903.3.1.3 or Section R309.1.1 of the California Residential Code.
310.5 Residential Group R-4. ¶
Residential Group R-4 occupancy shall include buildings, structures or portions thereof for more than six ambulatory clients, but not more than 16 persons, excluding staff, who reside on a 24-hour basis in a supervised residential environment and receive custodial care. The persons receiving care are capable of self-preservation. This occupancy classification may
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OCCUPANCY CLASSIFICATION AND USE
include a maximum six nonambulatory or bedridden clients (see Section 435, Special Provisions for Licensed 24-Hour Care Facilities in a Group R-2.1, R-3.1 or R-4). Group R-4 occupancies shall meet the requirements in Section 420. This group shall include, but not be limited to, the following:
Assisted living facilities such as: Residential care facilities, Residential care facilities for the elderly (RCFE), Adult residential facilities, Congregate living health facilities, Group homes.
Social rehabilitation facilities such as: Halfway houses, Community treatment programs, Work furlough programs, Alcoholism or drug abuse recovery or treatment facilities.
310.6 Large family day-care homes. See Section 455. ¶
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Ask AI about this code▸ Contents — 2025 California Building Code (Title 24, Part 2)
- Chapter 1 — ADMINISTRATION
- Chapter 2 — DEFINITIONS
-
▸ Chapter 3 — OCCUPANCY CLASSIFICATION AND USE
Overview- Section 301 — SCOPE
- Section 302 — OCCUPANCY CLASSIFICATION AND USE DESIGNATION
- Section 303 — ASSEMBLY GROUP A
- Section 304 — BUSINESS GROUP B
- Section 305 — EDUCATIONAL GROUP E
- Section 306 — FACTORY GROUP F
- Section 307 — HIGH-HAZARD GROUP H
- Section 308 — INSTITUTIONAL GROUP I
- Section 309 — MERCANTILE GROUP M
- Section 310 — RESIDENTIAL GROUP R
- Section 311 — STORAGE GROUP S
- Section 312 — UTILITY AND MISCELLANEOUS GROUP U
- Section 313 — LABORATORIES GROUP L [SFM]
- Section 314 — ORGANIZED CAMPS GROUP C [SFM]
- Chapter 4 — SPECIAL DETAILED REQUIREMENTS BASED ON OCCUPANCY A…
- Chapter 5 — GENERAL BUILDING HEIGHTS AND AREAS
- Chapter 6 — TYPES OF CONSTRUCTION
- Chapter 7 — FIRE AND SMOKE PROTECTION FEATURES
- Chapter 7A — MATERIALS AND CONSTRUCTION METHODS FOR EXTERIOR W…
- Chapter 8 — INTERIOR FINISHES
- Chapter 9 — FIRE PROTECTION AND LIFE SAFETY SYSTEMS
- Chapter 10 — MEANS OF EGRESS
- Chapter 11 — RESERVED
- Chapter 11A — HOUSING ACCESSIBILITY
- Chapter 11B — ACCESSIBILITY TO PUBLIC BUILDINGS, PUBLIC ACCOMM…
- Chapter 12 — INTERIOR ENVIRONMENT
- Chapter 13 — ENERGY EFFICIENCY
- Chapter 14 — EXTERIOR WALLS
- Chapter 15 — ROOF ASSEMBLIES AND ROOFTOP STRUCTURES
- Chapter 16 — STRUCTURAL DESIGN
- Chapter 16A — STRUCTURAL DESIGN
- Chapter 17 — SPECIAL INSPECTIONS AND TESTS
- Chapter 17A — SPECIAL INSPECTIONS AND TESTS
- Chapter 18 — SOILS AND FOUNDATIONS
- Chapter 18A — SOILS AND FOUNDATIONS
- Chapter 19 — CONCRETE
- Chapter 19A — CONCRETE
- Chapter 20 — ALUMINUM
- Chapter 21 — MASONRY
- Chapter 21A — MASONRY
- Chapter 22 — STEEL
- Chapter 22A — STEEL
- Chapter 23 — WOOD
- Chapter 24 — GLASS AND GLAZING
- Chapter 25 — GYPSUM PANEL PRODUCTS AND PLASTER
- Chapter 26 — PLASTIC
- Chapter 27 — ELECTRICAL
- Chapter 28 — MECHANICAL SYSTEMS
- Chapter 29 — PLUMBING SYSTEMS
- Chapter 30 — ELEVATORS AND CONVEYING SYSTEMS
- Chapter 31 — SPECIAL CONSTRUCTION
- Chapter 31A — SYSTEMS FOR WINDOW CLEANING OR EXTERIOR BUILDING…
- Chapter 31B — PUBLIC POOLS
- Chapter 31C — RADIATION
- Chapter 31D — FOOD ESTABLISHMENTS
- Chapter 31F — MARINE OIL TERMINALS
- Chapter 32 — ENCROACHMENTS INTO THE PUBLIC RIGHT-OF-WAY
- Chapter 33 — SAFEGUARDS DURING CONSTRUCTION
- Chapter 34 — RESERVED
- Chapter 35 — REFERENCED STANDARDS
- Appendix A — EMPLOYEE QUALIFICATIONS
- Appendix B — BOARD OF APPEALS
- Appendix C — GROUP U—AGRICULTURAL BUILDINGS
- Appendix D — FIRE DISTRICTS
- Appendix E — RESERVED
- Appendix F — RODENTPROOFING
- Appendix G — FLOOD-RESISTANT CONSTRUCTION
- Appendix H — SIGNS
- Appendix I — PATIO COVERS
- Appendix J — GRADING
- Appendix K — GROUP R-3 AND GROUP R-3.1 OCCUPANCIES PROTECTED B…
- Appendix L — EARTHQUAKE RECORDING INSTRUMENTATION
- Appendix M — TSUNAMI-GENERATED FLOOD HAZARDS
- Appendix N — REPLICABLE BUILDINGS
- Appendix O — PERFORMANCE-BASED APPLICATION
- Appendix P — SLEEPING LOFTS
- Appendix Q — EMERGENCY HOUSING