CRC · California Residential Code
Definition of 'Dwelling' and 'Dwelling unit' (how they affect occupancy and use)
A “dwelling” (per CRC/Title 24) is a building with one or two complete living units; a “dwelling unit” is a self‑contained space with permanent living, sleeping, eating, cooking and sanitation facilities. These definitions (see § R202 and the linked Title 24 definitions) determine which smoke‑alarm, egress, separation and ADU rules apply.
Last reviewed: July 6, 2026
What the code requires — 2-4 sentences
A dwelling is a building that contains one or two dwelling units, and a dwelling unit is a single unit that provides complete, independent living facilities (permanent provisions for living, sleeping, eating, cooking and sanitation). The California Residential Code points you to its definitions in Chapter 2 (see § R202) and, where terms are defined in other Title 24 parts, directs you to those definitions as well (§ R201.3) — for example, the California Building Code contains the standard text for DWELLING and DWELLING UNIT.
In plain English: if a building contains one or two complete, independent living spaces it fits the code’s definition of a dwelling; each complete living space is a dwelling unit.
Requirements in detail
Core definitions and how to read them
§ R202 is the CRC definitions section; it contains definitions used throughout the CRC and includes Accessory Dwelling Unit expressly. Where the CRC does not itself define a term, § R201.3 tells you to use the meaning in the California Building Standards Code (Title 24). That linkage is important because the Building Code text contains the dictionary entries for DWELLING and DWELLING UNIT.
The decision about whether a space is a dwelling unit depends on whether it provides the required permanent facilities (living, sleeping, eating, cooking, sanitation). If any of those permanent facilities are missing, the space is not a full dwelling unit under the code text cited above.
Decision-relevant dimensions (quick reference)
| Decision dimension | Critical value / test | Why it matters | Code Reference |
|---|---|---|---|
| How many units make a "dwelling" | One or two dwelling units | A building with 1–2 units meets the CBC/CRC “dwelling” definition and may be treated under residential provisions tuned to single- and two-family dwellings. | § R202 and building-code definitions |
| What is a "dwelling unit" | Must provide living, sleeping, eating, cooking, sanitation (all permanent) | Determines applicability of smoke alarms, egress, separations, and other occupant-safety rules tied to “dwelling unit.” | § R202 (definition via Title 24) |
| Accessory Dwelling Unit (ADU) | ADU = attached or detached residential dwelling unit with independent facilities | ADUs are treated as dwelling units for many building and safety rules; they are defined in § R202. | § R202 (Accessory Dwelling Unit) |
| Efficiency dwelling unit | All permanent provisions in a single room | Special sub-type; affects room-size and equipment considerations (if referenced elsewhere). | Efficiency definition in Title 24 definitions used by CRC |
| Terms not defined in CRC | Use California Building Standards Code (Title 24) meanings | Prevents inconsistent interpretation; establishes authoritative text for “dwelling”/“dwelling unit.” | § R201.3 |
How the definitions affect occupancy and use
- Classification and which CRC provisions apply turn on whether a space is a dwelling unit (e.g., smoke alarms, emergency escape requirements, dwelling-unit separation). See CRC chapters on alarms and egress that reference “dwelling unit” requirements.
- An Accessory Dwelling Unit is explicitly a dwelling unit under § R202, so an ADU will be subject to code provisions applicable to dwelling units unless a specific ADU exception applies.
- The number of dwelling units in a building (one, two, or more) determines if the structure fits the “dwelling” label or whether it is a multifamily building that may trigger additional CBC/CRC requirements (for example, accessibility or different sprinkler/egress rules captured elsewhere in the code). The CRC index and cross-references show where “Dwelling Unit” directs to separation, sprinkler, and egress sections.
Exceptions & special cases
- Accessory Dwelling Units (ADUs): ADUs are defined in § R202 as independent dwelling units on the same parcel as a primary residence; ADU-specific state laws and energy/ADU guidance can add or modify requirements (see ADU guidance excerpts). ADUs count as dwelling units for building-safety provisions unless a specific exception applies.
- Efficiency dwelling units: A special category where all permanent provisions are in one room — consult the efficiency dwelling-unit definition in the Title 24 definitions used by the CRC.
- Terms defined in other codes: Where the CRC defers, the California Building Code (and other Title 24 parts) provide the definition. That matters when CRC text is silent — the fallback is § R201.3.
- Dormitories, shelters and other residential-style spaces: The building-code definition notes situations (e.g., dormitory rooms, shelters) where sleeping accommodations may exist but other facilities are shared; these are treated differently for Chapter 11A and other specific parts. Check the referenced notes in the Title 24 definitions.
If a particular CRC chapter or local amendment seems to treat a given arrangement differently, refer to the specific section; R202/respective Title 24 definitions are the starting point. If you need a determination for a specific use (e.g., shared cooking or sanitation), that factual situation decides whether the unit is a full dwelling unit or a different use.
Common mistakes
- Treating every residential building as a "dwelling." The CRC/Title 24 dwelling definition covers one or two units only; buildings with more units are not within that narrow label. Check § R202 and the Title 24 definitions.
- Assuming a room with a bed is a dwelling unit. Without permanent cooking and sanitation facilities the space is not a full dwelling unit under the definition. Verify presence of living, sleeping, eating, cooking and sanitation.
- Ignoring R201.3. When CRC text is silent on a term, the building-code (Title 24) meaning controls — don’t apply plain-English usages instead of the code text. § R201.3 governs this.
- Overlooking ADU treatment. ADUs are explicitly defined in § R202 and are dwelling units for many purposes; local ADU laws can modify how ADUs are regulated but they remain dwelling units as defined by the CRC/Title 24.
Worked example — duplex vs. multifamily
Scenario: You have a two‑story building with two completely independent units. Each unit has a kitchen, bathroom(s), living room and sleeping room(s).
- Count: There are two dwelling units. Under the code text this is a dwelling because the building contains one or two dwelling units. The Building Code definition of DWELLING and DWELLING UNIT (referenced by CRC) supports this.
- Consequences:
- Each unit is a dwelling unit subject to smoke-detector requirements applicable to dwelling units intended for human occupancy (see § R310.8.2 and related CRC alarm sections). Install required smoke alarms per that section for each dwelling unit.
- Dwelling‑garage separation, unit separation and other residential‑unit provisions in Chapter 3 and elsewhere apply per the references to “Dwelling Unit” (see R302-series cross references).
- Contrast: If the same building contained three independent units, it would not meet the CBC/CRC short definition of “dwelling” (one or two units). That changes how some provisions are applied and may bring in additional CBC/CRC requirements for multifamily buildings (accessibility, sprinkler counts, etc.). For such a determination consult the relevant multifamily sections referenced elsewhere in the code.
Related provisions (quick list)
- § R202 — Definitions (CRC) — see Accessory Dwelling Unit and linkage to Title 24 definitions.
- § R201.3 — Terms defined in other codes; CRC uses Title 24 (California Building Standards Code) meanings when it does not define a term.
- § R302.2 — Dwelling-unit separation (references in CRC index).
- § R302.3 — (See index cross‑references to Dwelling Unit separation).
- § R302.6 — Dwelling‑garage separation and related requirements referenced from CRC index.
- § R310.8.2 — Smoke‑detector installation timing/requirements for dwelling units intended for human occupancy (CRC).
- § R319 — Emergency escape and rescue openings (applies to dwelling units and is cross‑referenced in the CRC).
If you need authoritative, line‑for‑line text for these definitions or want the exact wording used in Title 24 for DWELLING and DWELLING UNIT, I can pull the exact code text from the Title 24 files you provided and annotate it section‑by‑section.
Code references
Grounded in the retrieved California Residential Code — click a citation to read the verbatim passage:
CRC § 2-26 High relevance — show source text
DRIVE AISLE. [DSA-AC] A vehicular way provided within a parking facility that connects vehicular entrances, parking stalls, electric vehi- cle charging stations, passenger loading zones and vehicular exits.
DRIVE-UP ELECTRIC VEHICLE CHARGING STATION. [DSA-AC] An electric vehicle charging station in which use is limited to 30 minutes maximum and is provided at a location where the electric vehicle approaches in the forward direction, stops in the vehicle space, charges the vehicle and proceeds forward to depart the vehicle space. The arrangement of a drive-up electric vehicle charger and its associated vehicle space is similar to a gasoline filling station island.
DRIVEWAY. [DSA-AC] A vehicular way providing access between a public way and a building, parking facility, or other off-street area. A driveway may provide access to drive aisles in a parking facility.
[BS] DRY FLOODPROOFING. A combination of design modifications that results in a building or structure, including the attendant utilities and equipment and sanitary facilities, being watertight with walls substantially impermeable to the passage of water and with structural components having the capacity to resist loads as identified in ASCE 7.
[F] DRY-CHEMICAL EXTINGUISHING AGENT. A powder composed of small particles, usually of sodium bicarbonate, potassium bicarbonate, urea-potassium-based bicarbonate, potassium chloride or monoammonium phosphate, with added particulate material supplemented by special treatment to provide resistance to packing, resistance to moisture absorption (caking) and the proper flow capabilities.
[A] 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.
[A] 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. [HCD 1-AC] For the purposes of Chapter 11A, a single unit of residence for a family of one or more persons. Examples of dwelling units covered by Chapter 11A include condominiums, an apartment unit within an apartment building, and other types of dwellings in which sleeping accommodations are provided but toileting or cooking facilities are shared by occupants of more than one room or portion of the dwelling. Examples of the latter include dormitory rooms and sleeping accommodations in shelters intended for occupancy as residences for homeless persons.
[BG] DWELLING UNIT, EFFICIENCY. A dwelling unit where all permanent provisions for living, sleeping, eating and cooking are contained in a single room.
DWELLING UNIT OR SLEEPING UNIT, MULTISTORY. See “Multistory unit.”
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DEFINITIONS
EFFECTIVE PARTICLE SIZE. The theoretical size of a sieve in mm that will pass 10 percent by weight of sand.
EFFICIENCY DWELLING UNIT. [HCD 1] A dwelling unit constructed in accordance with Health and Safety Code Section 17958.1 or the Cali- fornia Building Code Section 1208.4.
[BE] EGRESS COURT. A court or yard which provides access to a public way for one or more exits.
CRC § 2-3 Medium relevance — show source text
SYSTEM||||X|||||||||||||||||||| |VENTILATION||||X|||||||||||||||||||| |WATER HEATER||||X|||||||||||||||||||| |WHOLE-HOUSE MECHANICAL
VENTILATION SYSTEM||||X|||||||||||||||||||| |WILDLAND-URBAN INTERFACE (WUI)|||X|||||||||||||||||||||The state agency does not adopt sections identified with the following symbol: †
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Part II—Definitions
2 DEFINITIONS
User notes:
About this chapter: Codes, by their very nature, are technical documents. Every word, term and punctuation mark can add to or change the meaning of a technical requirement. It is necessary to maintain a consensus on the specific meaning of each term contained in the code. Chapter 2 performs this function by stating clearly what specific terms mean for the purpose of the code.
ICC code development note: Code change proposals to definitions in this chapter preceded by a bracketed letter are considered by the IRC—Building Code Development Committee [RB], the IRC—Mechanical/Plumbing Code Development Committee [MP] or the IECC—Residential Code Development Committee [RE] during the Group B (2025) Code Development Cycle.
SECTION R201—GENERAL
R201.1 Scope. Unless otherwise expressly stated, the following words and terms shall, for the purposes of this code, have the meanings indicated in this chapter.
R201.2 Interchangeability. Words used in the present tense include the future; words in the masculine gender include the feminine and neuter; the singular number includes the plural and the plural, the singular.
R201.3 Terms defined in other codes. Where terms are not defined in this code such terms shall have the meanings ascribed in the California Building Standards Code, Title 24, California Code of Regulations.
R201.4 Terms not defined. Where terms are not defined through the methods authorized by this section, such terms shall have ordinarily accepted meanings such as the context implies.
For applications listed in Section 1.11 regulated by the Office of the State Fire Marshal, where terms are not defined through the meth- ods authorized by this section, such terms shall have ordinarily accepted meanings such as the context implies. Webster’s Third New International Dictionary of the English Language, Unabridged, shall be considered as providing ordinarily accepted meanings.
SECTION R202—DEFINITIONS
[RB] ACCESS (TO). That which enables a device, an appliance or equipment to be reached by ready access or by a means that first requires the removal or movement of a panel, door or similar obstruction.
ACCESSORY DWELLING UNIT. [HCD 1 & HCD 2] An attached or detached residential dwelling unit that provides complete independent living facilities for one or more persons and is located on a lot with a proposed or existing primary residence. Accessory dwelling units shall include permanent provisions for living, sleeping, eating, cooking and sanitation on the same parcel as the single-family or multifamily dwelling is or will be situated. (See Government Code Section 65852.2)
CRC § 8.2 Medium relevance — show source text
Note: It is the intent of this section that every existing occupancy need not mandatorily conform with the requirements for new construction. Reasonable judgment in the application of requirements must be exercised by the enforcing agency.
R310.8.2 Health and Safety Code Section 13113.7. For purposes of clarification, Health and Safety Code Section 13113.7 is repeated. a. Except as otherwise provided in this section, a smoke detector, approved and listed by the State Fire Marshal pursuant to Section 13114, shall be installed, in accordance with the manufacturer's instructions in each dwelling intended for human occupancy within the earliest applicable time period as follows: 1. For all dwelling units intended for human occupancy, upon the owner's application on or after January 1, 1985, for a permit for alterations, repairs, or additions, exceeding one thousand dollars ($1,000). 2. For all other dwelling units intended for human occupancy on or after January 1, 1987. However, if any local rule, regulation or ordinance, adopted prior to the compliance dates specified in paragraphs (1) and (2) requires installation in a dwelling unit intended for human occupancy of smoke detector, which receive their power from the electrical system of the building and requires compliance with the local rule, regulation or ordi- nance at a date subsequent to the dates specified in this section, the compliance date specified in the rule, regulation or ordinance shall, but only with respect to the dwelling units specified in this section, take precedence over the dates specified in this section. The State Fire Marshal may adopt regulations exempting dwellings intended for human occupancy with fire sprin- kler systems from the provisions of this section, if he or she determines that a smoke detector is not reasonably necessary for fire safety in the occupancy. Unless prohibited by local rules, regulations or ordinances, a battery-operated smoke detector which otherwise meets the standards adopted pursuant to Section 13114 for smoke detectors, satisfies the requirements of this section.
b. “Dwelling units intended for human occupancy,” as used in this section, includes a duplex, lodging house, apartment complex, hotel, motel, condominium, stock cooperative, time-share project or dwelling unit of a multiple-unit dwelling complex. For the purpose of this part, “dwelling units intended for human occupancy” does not include manufactured homes as defined in Section 18007, mobile homes as defined in Section 18008, and commercial coaches as defined in Section 18001.8.
c. The owner of each dwelling unit subject to this section shall supply and install smoke detectors required by this section in the locations and in the manner set forth in the manufacturer's instructions, as approved by the State Fire Marshal’s regula- tions. In the case of apartment complexes and other multiple- dwelling complexes, a smoke detector shall be installed in the common stairwells. All fire alarm warning systems supplemental to the smoke detector shall also be listed by the State Fire Marshal.
CRC § 1.11 Medium relevance — show source text
R201.2 Interchangeability. Words used in the present tense include the future; words in the masculine gender include the feminine and neuter; the singular number includes the plural and the plural, the singular.
R201.3 Terms defined in other codes. Where terms are not defined in this code such terms shall have the meanings ascribed in the California Building Standards Code, Title 24, California Code of Regulations.
R201.4 Terms not defined. Where terms are not defined through the methods authorized by this section, such terms shall have ordinarily accepted meanings such as the context implies.
For applications listed in Section 1.11 regulated by the Office of the State Fire Marshal, where terms are not defined through the meth- ods authorized by this section, such terms shall have ordinarily accepted meanings such as the context implies. Webster’s Third New International Dictionary of the English Language, Unabridged, shall be considered as providing ordinarily accepted meanings.
SECTION R202—DEFINITIONS
[RB] ACCESS (TO). That which enables a device, an appliance or equipment to be reached by ready access or by a means that first requires the removal or movement of a panel, door or similar obstruction.
ACCESSORY DWELLING UNIT. [HCD 1 & HCD 2] An attached or detached residential dwelling unit that provides complete independent living facilities for one or more persons and is located on a lot with a proposed or existing primary residence. Accessory dwelling units shall include permanent provisions for living, sleeping, eating, cooking and sanitation on the same parcel as the single-family or multifamily dwelling is or will be situated. (See Government Code Section 65852.2)
[RB] ACCESSORY STRUCTURE. A structure that is accessory to and incidental to that of the dwelling(s) or townhouse(s) and that is located on the same lot.
[RB] ADDITION. An extension or increase in floor area, number of stories or height of a building or structure.
[RB] ADHERED STONE OR MASONRY VENEER. Stone or masonry veneer secured and supported through the adhesion of an approved bonding material applied to an approved backing.
AGED HOME OR INSTITUTION. A facility used for the housing of persons 65 years of age or older in need of care and supervision. (See defi- nition of “care and supervision.”)
[MP] AIR, OUTDOOR. Ambient air that enters a building through a ventilation system, through intentional openings for natural ventilation or by infiltration.
[MP] AIR, TRANSFER. Air moved from one indoor space to another.
[MP] AIR ADMITTANCE VALVE. A one-way valve designed to allow air into the plumbing drainage system where a negative pressure develops in the piping. This device shall close by gravity and seal the terminal under conditions of zero differential pressure (no flow conditions) and under positive internal pressure.
[MP] AIR BREAK (DRAINAGE SYSTEM). An arrangement where a discharge pipe from a fixture, appliance or device drains indirectly into a receptor below the flood-level rim of the receptor and above the trap seal.
[MP] AIR CIRCULATION, FORCED. A means of providing space conditioning utilizing movement of air through ducts or plenums by mechanical means.
[MP] AIR GAP, DRAINAGE SYSTEM. The unobstructed vertical distance through free atmosphere between the outlet of a waste pipe and the flood-level rim of the fixture or receptor into which it is discharging.
CRC § 9.1 Medium relevance — show source text
Defined R202 Chimneys Caps R1003.9.1 Clearance R1003.18 Corbeling R1003.5 Crickets R1003.20 Design (masonry) R1003.1 Factory-built R1005 Fireblocking R1003.19 Fireplaces Chapter 10 Flue area R1003.14, R1003.15 Flue lining R1003.11 Load R1003.8 Multiple flue R1003.14 Rain caps R1003.9.3 Spark arrestors R1003.9.2 Termination R1003.9
Wall thickness R1003.10
Clay Tiles R905.3
Cleanout Masonry chimney R1003.17 Climate Types R301.2 Climate Zones R202, R702.7.3, Table R702.7(5) Columns R407
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INDEX
Live load R301.5
Nominal sizes R301.8
Roof load R301.6
Seismic R301.2.2
Snow loads R301.2.3 Story height R301.3 Sunrooms R301.2.1.1.1
Wind R301.2.1
Doors
Egress R318.2 Exterior R318.3, R609 Glazing R324 Draftstopping R302.12, R502.13 Drainage Foundation R405 Site drainage R300 Ducts
Defined R202 Dwelling-garage wall and ceiling penetration R302.5.2 System, definition R202 Dwelling Unit Separation R302.2, R302.3 Sprinklers (see Automatic Sprinkler System)
Electric Vehicle Charging Stations R317.6 Elevator R323.1, R323.3 Emergency Escape and Rescue Openings R319
Additions R319.6
Area wells R319.4 Bars, grilles, covers and screens R319.4.4
Basements, existing R319.7 Dimensions R319.2
Doors R319.3
Replacement window R319.5 Under decks and porches R319.2.4 Where required R319.1 Window fall protection R321.2 Emergency Housing Appendix CJ Energy Storage Systems R328 ESS vehicle impact protection Figure R330.8.1 Maximum aggregate ratings of ESS Table R330.5 Protection from impact R330.8 Toxic and highly toxic gas R330.12 Entry 1.8.5, R104.4 Existing Buildings Appendix BO Administrative R101.2, R102.6, R105.1, R105.8, R106.2, R113.1, R113.2 Basements R313.1.2, R319.7 Carbon monoxide alarms R311.2.2, R311.5, R311.6 Flood R104.3.1
CRC § 798.9. Medium relevance — show source text
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Ch. 290 — 16 —
(iii) The local government has made a binding finding within their local ordinance that the ordinance is more protective than the provisions of this section.
(2) A residential real property shall not be subject to both a local ordinance requiring just cause for termination of a residential tenancy and this section.
(3) A local ordinance adopted after September 1, 2019, that is less protective than this section shall not be enforced unless this section is repealed.
(j) Any waiver of the rights under this section shall be void as contrary to public policy.
(k) For the purposes of this section, the following definitions shall apply: (1) “Owner” includes any person, acting as principal or through an agent, having the right to offer residential real property for rent, and includes a predecessor in interest to the owner.
(2) “Residential real property” means any dwelling or unit that is intended for human habitation, including any dwelling or unit in a mobilehome park.
(3) “Tenancy” means the lawful occupation of residential real property and includes a lease or sublease.
( l ) This section shall not apply to a homeowner of a mobilehome, as defined in Section 798.9.
(m) This section shall become operative on April 1, 2024. (n) This section shall remain in effect only until January 1, 2030, and as of that date is repealed.
SEC. 3. Section 1947.12 of the Civil Code is amended to read: 1947.12. (a) (1) Subject to subdivision (b), an owner of residential real property shall not, over the course of any 12-month period, increase the gross rental rate for a dwelling or a unit more than 5 percent plus the percentage change in the cost of living, or 10 percent, whichever is lower, of the lowest gross rental rate charged for that dwelling or unit at any time during the 12 months prior to the effective date of the increase. In determining the lowest gross rental amount pursuant to this section, any rent discounts, incentives, concessions, or credits offered by the owner of such unit of residential real property and accepted by the tenant shall be excluded. The gross per-month rental rate and any owner-offered discounts, incentives, concessions, or credits shall be separately listed and identified in the lease or rental agreement or any amendments to an existing lease or rental agreement.
(2) If the same tenant remains in occupancy of a unit of residential real property over any 12-month period, the gross rental rate for the unit of residential real property shall not be increased in more than two increments over that 12-month period, subject to the other restrictions of this subdivision governing gross rental rate increase.
(b) For a new tenancy in which no tenant from the prior tenancy remains in lawful possession of the residential real property, the owner may establish the initial rental rate not subject to subdivision (a). Subdivision (a) is only
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applicable to subsequent increases after that initial rental rate has been established.
(c) A tenant of residential real property subject to this section shall not enter into a sublease that results in a total rent for the premises that exceeds the allowable rental rate authorized by subdivision (a). Nothing in this subdivision authorizes a tenant to sublet or assign the tenant’s interest where otherwise prohibited.
CRC § 2.3.1 Medium relevance — show source text
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Concrete Capillary break R506.2.3.1 Compressive strength R402.2 Floors (on ground) R506 Tile (roof) R905.3 Weathering Figure R301.2(1), R402.2 Construction
3D-printed Appendix BM Cavity wall masonry R608 Cob Appendix BK Extended plate walls Appendix BN Flood-resistant R306
Floors Chapter 5 Footings R403 Foundation material R402
Foundation walls R404
Foundations Chapter 4 Hemp-lime Appendix BL Masonry R606, R607, R608, R610 Pollutant control R340 Roofs Chapter 8 Steel framing R505, R603, R804 Strawbale Appendix BJ Straw-clay Appendix BI Walls Chapter 6 Waste R334.1 Wood framing R502, R602, R802 Construction Documents R106, R306.3.9
Court Emergency escape and rescue openings R319.1, R319.2.4 Means of egress R318.1 Natural light R325.1.1 Covering Exterior R703
Interior R702 Roof Chapter 9 Wall Chapter 7 Crawl Space R408
Access R408.4
Damper Fireplace R1001.7.1 Dampproofing R406 Day Care Appendix BD Defined R202 Large family day-care homes R336 Dead Loads R301.4
Decay Protection against R304 Deck
Attachment R318.5 Supported by exterior wall R507 Wood/plastic composite boards R507.2.2
Definitions Building R202 Mechanical system R202 Plumbing R202 Design Criteria R301 Alternative provisions R301.1.1 Application R301.1 Climatic and geographic R301.2 Dead load R301.4
Deflection R301.6 Engineered design R301.1.3
Accessibility R322 Accessory Dwelling Unit R202 Authority to Enforce Automatic Fire Sprinkler Systems 1.8.9.1, R313.2 Accessory Structure Elevations R306.3.2
Energy R330.5 Exterior walls R302.1
Scope R101.2 Addition (see also Existing Buildings) Carbon monoxide alarms R311.2.2 Change of occupancy R110.1 Construction R302.2.3
CRC § 2-1 Medium relevance — show source text
RESIDENTIAL
CODE|||||||||†||†||†|||||||||| |LOW-RISE
RESIDENTIAL BUILDING|||||||||†||†||†|||||||||| |PLANTS|||||||||†||†||†|||||||||| |RESIDENTIAL BUILDING|||||||||†||†||†|||||||||| |RESILIENT FLOORING|||||||||†||†||†||||||||||The state agency does not adopt sections identified by the following symbol: †.
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2 DEFINITIONS
SECTION 201—GENERAL
201.1 Scope. Unless otherwise stated, the following words and terms shall, for the purposes of this code, have the meanings shown in this chapter.
201.2 Interchangeability. Words used in the present tense include the future; words stated in the masculine gender include the feminine and neuter; the singular number includes the plural and the plural, the singular.
201.3 Terms defined in other documents. Where terms are not defined in this code and are defined in the California Building Stan- dards Code or other referenced documents, such terms shall have the meanings ascribed to them as in those publications.
201.4 Terms not defined. Where terms are not defined as specified in this section, such terms shall have ordinarily accepted meanings such as the context implies.
SECTION 202—DEFINITIONS
2 X 2 RULE. [BSC-CG] Visual markers are the most effective collision deterrents if spaced no more than 2 inches (5.1 cm) apart, a distance through which most birds cannot fly.
ACCESSORY DWELLING UNIT. [HCD] An attached or detached residential dwelling unit that provides complete independent living facilities for one or more persons and is located on a lot with a proposed or existing primary residence. Accessory dwelling units shall include permanent provisions for living, sleeping, eating, cooking and sanitation on the same parcel as the singlefamily or multifamily dwelling is or will be situated. (See Government Code Section 65852.2.)
ACCESSORY OCCUPANCIES. [HCD] Occupancies that are ancillary to the main occupancy of residential building(s) or portions thereof. Accessory occupancies shall include, but are not limited to, Group U occupancies. (See Section 312 of the California Build- ing Code. )
ACCESSORY STRUCTURE. [HCD] A structure that is accessory to and incidental to that of the dwelling(s) and that is located on the same lot.
ADDITION. An extension or increase in floor area of an existing building or structure.
ADHESIVE MARKER. [BSC-CG] An individual marker(s) applied to the first surface of glass (surface 1) in a pattern or as a custom decal.
ADJUST. To regulate fluid flow rate and air patterns at the terminal equipment, such as to reduce fan speed or adjust a damper.
AGRIFIBER PRODUCTS. Agrifiber products include wheatboard, strawboard, panel substrates and door cores, not including furniture, fixtures and equipment (FF&E) not considered base building elements.
CRC § 5.2 Medium relevance — show source text
Defined R202 Dwelling-garage wall and ceiling penetration R302.5.2 System, definition R202 Dwelling Unit Separation R302.2, R302.3 Sprinklers (see Automatic Sprinkler System)
Electric Vehicle Charging Stations R317.6 Elevator R323.1, R323.3 Emergency Escape and Rescue Openings R319
Additions R319.6
Area wells R319.4 Bars, grilles, covers and screens R319.4.4
Basements, existing R319.7 Dimensions R319.2
Doors R319.3
Replacement window R319.5 Under decks and porches R319.2.4 Where required R319.1 Window fall protection R321.2 Emergency Housing Appendix CJ Energy Storage Systems R328 ESS vehicle impact protection Figure R330.8.1 Maximum aggregate ratings of ESS Table R330.5 Protection from impact R330.8 Toxic and highly toxic gas R330.12 Entry 1.8.5, R104.4 Existing Buildings Appendix BO Administrative R101.2, R102.6, R105.1, R105.8, R106.2, R113.1, R113.2 Basements R313.1.2, R319.7 Carbon monoxide alarms R311.2.2, R311.5, R311.6 Flood R104.3.1
Smoke alarms R310.2.2, R310.6 Stairways R318.7.9 Windows, replacement R319.5 Exterior Balconies and elevated walking surfaces R106.1.6
Covering R703 Insulation finish systems R703.9 Lath R703.7.1
Plaster R703.7 Exterior Insulation and Finish Systems (EIFS) 703.9
Exterior Wall
Construction R302.1
Fire-resistance rating R302.1
Factory Built Chimneys R1005 Fireplace stoves R1005.3 Fireplaces R1004 Fastening Table R602.3(1) Fees, Permit R108 Finishes Flame spread and smoke density R302.9 For ceilings R805 Interior R302.9, R311, R702 Fire Sprinkler System (see Automatic Sprinkler System) Ceiling configurations R309.3.4.1.1, R309.3.4.1.2, R309.3.4.1.3 Flow rate R309.3.4.1 Fireblocking Barrier between stories R302.11,
R602.8 Chimney R1003.19 Fireplace R1001.12 Fireplaces Chapter 10 Clearance R1001.11 Corbeling R1001.8 Factory-built R1004 Fireblocking R1001.12 Walls R1001.5
Fire-Resistant Construction R302 Draftstopping R302.2 Dwelling-garage fire separation R302.6 Dwelling-garage opening and penetration R302.5 Exterior walls R302.1 Fireblocking R302.11 Floors R302.13
Foam plastics R302.8 Insulation R302.10, R302.14 Penetrations R302.4
CRC § 1102A.3.2 Medium relevance — show source text
The minimum number of multifamily dwelling units which must comply with this section shall be calculated using the total number of all multistory dwelling units in buildings on a site which are subject to this section. Any fraction thereof shall be rounded to the next highest whole number.
1102A.3.2 Multistory dwelling units in buildings with one or more elevators. Multistory dwelling units contained in buildings with elevators shall comply with this section. For multistory dwelling units in buildings with elevators, the story of the unit that is served by the building elevator is considered a ground floor and the primary entry floor to the unit and shall comply with the following:
1. At least 1 powder room or bathroom shall be located on the primary entry level.
2. At least 1 kitchen shall be located on the primary entry level.
3. All rooms or spaces located on the primary entry level shall be served by an accessible route and shall comply with Division IV.
1102A.4 Temporary restrictions. During periods of partial or restricted use of a building or facility, the entrances used for primary access shall be accessible to and usable by persons with disabilities.
SECTION 1103A—DESIGN AND CONSTRUCTION
1103A.1 General. When buildings are required to be accessible, they shall be designed and constructed as provided in this chapter.
11A-4 2025 CALIFORNIA BUILDING CODE
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
HOUSING ACCESSIBILITY
SECTION 1104A—COVERED MULTIFAMILY DWELLINGS
1104A.1 General. All ground-floor dwelling units in nonelevator buildings shall be adaptable and on an accessible route, unless an accessible route is not required as determined by site impracticality provisions in Section 1150A. For buildings with elevators, see Section 1106A.
Multistory dwelling units shall comply with Section 1102A.3.
1104A.2 Ground floors above grade. Where the first floor containing dwelling units in a building is above grade, all units on that floor shall be served by an accessible route. This floor will be considered a ground floor and all dwelling units are considered covered multi- family dwelling units.
Exception: Carriage units as defined in Chapter 2 and regulated only by the Department of Housing and Community Development as referenced in Section 1.8.2.1.2.
Multistory dwelling units shall comply with Section 1102A.3.
SECTION 1105A—GARAGES, CARPORTS AND PARKING FACILITIES
1105A.1 General. Garages, carports and other parking facilities, which are accessory to covered multifamily dwelling units, shall be accessible as required in Section 1109A.
SECTION 1106A—SITE AND BUILDING CHARACTERISTICS
1106A.1 General. Covered multifamily dwellings with elevators shall be designed and constructed to provide at least one accessible entrance on an accessible route, regardless of terrain or unusual characteristics of the site. Covered multifamily dwellings without eleva- tors shall be designed and constructed to provide at least one accessible entrance on an accessible route unless terrain or unusual characteristics of the site prevent an accessible route based on the conditions listed below: 1. _**Accessible entrance.
CRC § 2.4 Medium relevance — show source text
Court Emergency escape and rescue openings R319.1, R319.2.4 Means of egress R318.1 Natural light R325.1.1 Covering Exterior R703
Interior R702 Roof Chapter 9 Wall Chapter 7 Crawl Space R408
Access R408.4
Damper Fireplace R1001.7.1 Dampproofing R406 Day Care Appendix BD Defined R202 Large family day-care homes R336 Dead Loads R301.4
Decay Protection against R304 Deck
Attachment R318.5 Supported by exterior wall R507 Wood/plastic composite boards R507.2.2
Definitions Building R202 Mechanical system R202 Plumbing R202 Design Criteria R301 Alternative provisions R301.1.1 Application R301.1 Climatic and geographic R301.2 Dead load R301.4
Deflection R301.6 Engineered design R301.1.3
Accessibility R322 Accessory Dwelling Unit R202 Authority to Enforce Automatic Fire Sprinkler Systems 1.8.9.1, R313.2 Accessory Structure Elevations R306.3.2
Energy R330.5 Exterior walls R302.1
Scope R101.2 Addition (see also Existing Buildings) Carbon monoxide alarms R311.2.2 Change of occupancy R110.1 Construction R302.2.3
Frost protection R403.1.4.1 Scope R101.2, R102.6.1 Smoke alarms R310.2.2 Address (Site) R308 Administration, California Chapter 1, Division 1
General 1.1 Dept. of Housing and Community Development 1.8 Office of the State Fire Marshal 1.11 Administration, Division II Chapter 1 Applicability R102 Certificate of occupancy R110 Construction documents R106 Department of building safety R103 Duties and Powers R104
Fees R106
Inspections R109 Means of appeals R112 Permits R105, R105.5.1 Purpose R101.3 Service utilities R111 Stop work order R114 Temporary structures and uses R107 Violations R113 Aging-in-place Design and Fall Prevention R327
Doorbell buttons R327.1.4 Electrical receptacle outlet, switch and control heights R327.1.2 Interior doors R327.1.3 Reinforcement for grab bars R327.1.1 Allowable Spans Of floor joists R502.3, R505.3.2 Of headers R602.7, R603.6 Of rafters and ceiling joists R802.4, R802.5, R804.3.1, R804.3.2 Alternate Materials (see Materials) R104.11 Alterations (see Existing Buildings) Anchor Bolts R403.1.6
Appeal Board of 1.8.8, Appendix AA Means of 1.8.8, R112 Appliance Flue area R1003.14
CRC § 1.1 Medium relevance — show source text
CBC—25: California Building Code R101.2, R202, R301.1.1, R301.1.3, R301.2.1.1, R301.2.2.1.1, R301.2.2.1.2, R301.3, Table R302.1(1), Table R302.1(2), R302.2.1, R302.2.2, R302.3, R302.15.4, R322.1, R322.3, R324.5, R403.1.8, Table R602.10.3(3), Table R606.12.2.1, R609.2, R905.10.3
CEBC—25: California Existing Building Code [®]
R110.2, N1109.2
CFC—25: California Fire Code [®]
R102.6, R329.2, N1109.2, M2201.7, G2402.3, G2412.2
CWUIC—25: California Wildland-Urban Interface Code
R102.8, R337, R806.1.1, R907.1.1
ICC 400—2022: Standard on the Design and Construction of Log Structures
R301.1.1, R502.1.4, R602.1.4, R703.1, R802.1.3
ICC 500—2020: ICC/NSSA Standard for the Design and Construction of Storm Shelters
R307.1
ICC 600—2020: 2020 Standard for Residential Construction in High-Wind Regions
R301.2.1.1
ICC 1100—2019: Standard for Spray-applied Polyurethane Foam Plastic Insulation
R303.1.1
IPMC—24: International Property Maintenance Code [®]
R102.6
ISO International Organization for Standardization Chemin de Blandonnet 8 Geneva, Switzerland CP 401 - 1214
8336—2009: Fibre-cement Flat Sheets—Product Specification and Test Methods Table R503.2.1.1(1), Table R503.2.1.1(2), Table R602.3(2), Table R702.4.2, R703.10.1, R703.10.2
44-16 2025 CALIFORNIA RESIDENTIAL CODE
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
REFERENCED STANDARDS
NFPA National Fire Protection Association 1 Batterymarch Park Quincy, MA 02169-7471
13D— 25 : Standard for the Installation of Sprinkler Systems in One- and Two-Family Dwellings and Manufactured Homes as amended*
R309.1.1, R309.2.1, R309.3.1, R309.3.1.1, R309.3.2.3, R309.3.6.1, R329.6.2.1
*See California Fire Code for amendments
*NFPA 13D, Amended Sections as follows:
CRC § 65852.150 Medium relevance — show source text
New Government Code Sections Previous Government Code Sections Col2 ~~Article 1. General Provisions ~~ ~~Article 1. General Provisions ~~ 6631065852.150 (a)6631165852.150 (b)6631265852.150 (c)66313General Definition Section
65852.2 (j)
65852.22 (j)**Article 2. Accessory Dwelling Unit Approvals ****Article 2. Accessory Dwelling Unit Approvals **6631465852.2 (a)(1)(A),
(D)(i)-(xii),
(a)(4)-(5)6631565852.2 (a)(8)6631665852.2 (a)(6)6631765852.2 (a)(3),
(a)(7)6631865852.2 (a)(9)
65852.2 (a)(2)47
New Government Code Sections Previous Government Code Sections Col2 6631965852.2 (a)(10)6632065852.2 (b)6632165852.2 (c)6632265852.2 (d)6632365852.2 (e)6632465852.2 (f)6632565852.2 (g)6632665852.2 (h)6632765852.2 (i)6632865852.2 (k)6632965852.2 (l)6633065852.2 (m)6633165852.2 (n)6633265852.23.**Article 3. Junior Accessory Dwelling Units **~~**_Article 3. CRC § 17920.3 Medium relevance — show source text
14
additional two feet for roof pitch to align with the roof pitch of the primary dwelling unit.” (Gov. Code, §§ 66321, subd. (b)(4)(B); 66323, subd. (a)(2)(B).) Increases the height to 18 feet for a detached ADU that is “on a lot with an existing or proposed multifamily, multistory dwelling.” (Gov. Code, § 66321, subd. (b)(4)(B).)
Attached ADU Height Limitations. Establishes the maximum height limitation that may be imposed by a local agency on an attached ADU to 25 feet, or the existing primary dwelling height limit if lower than 25 feet. Does not require a local agency to allow an ADU to exceed two stories (Gov. Code, § 66321, subd. (b)(4)(D)).
Parking Standards. Prohibits local agencies from imposing parking in a number of specific circumstances (Gov. Code, § 66322, subd. (a)).
Zoning Nonconformance & Building Code Violations. Prohibits local agencies from denying an ADU permit due to the correction of “nonconforming zoning conditions, building code violations, or unpermitted structures that do not present a threat to public health and safety and are not affected by the construction of the accessory dwelling unit.” (Gov. Code, § 66322, subd. (b).) The prohibition was also added to Government Code section 66336 to apply to JADUs.
Multifamily Dwellings. Prohibits a permitting agency from requiring “any modification of the existing multifamily dwelling as a condition of approving the application to construct an accessory dwelling unit” if the existing multifamily dwelling has “a rear or side setback of less than four feet...” (Gov. Code, § 66323, subd. (a)(4)(B)).
Permitting Agency Definition . Adds definition of a permitting agency as “any entity that is involved in the review of a permit for an accessory dwelling unit or junior accessory dwelling unit and for which there is no substitute, including, but not limited to, applicable planning departments, building departments, utilities, and special districts.” (Gov. Code, § 66313, subd. (k).)
Unpermitted ADUs. Precludes a local agency from denying a permit for an unpermitted ADU that was constructed before January 1, 2018, because the ADU violates building standards or because the ADU does not comply with State ADU Law or a local ordinance. (Gov. Code, § 66332, subd. (a).) This prohibition does not apply if the local agency makes a finding that “correcting the violation is necessary to protect the health and safety of the public or occupants of the structure” (Gov. Code, § 66332, subd. (b)) or to a building that is deemed substandard pursuant to Health and Safety Code section 17920.3 (Gov. Code, § 66332, subd. (c)).
- Enclosed Uses . Considers enclosed uses within the residence, such as attached garages, to be “a part of the proposed or existing single-family residence” for the purposes of JADUs (Gov. Code, § 66333, subd. (d)).
15
CRC § 2.7 Medium relevance — show source text
(d) This section shall not apply to the following residential real properties: (1) Housing restricted by deed, regulatory restriction contained in an agreement with a government agency, or other recorded document as affordable housing for persons and families of very low, low, or moderate income, as defined in Section 50093 of the Health and Safety Code, or subject to an agreement that provides housing subsidies for affordable housing for persons and families of very low, low, or moderate income, as defined in Section 50093 of the Health and Safety Code or comparable federal statutes.
(2) Dormitories owned and operated by an institution of higher education or a kindergarten and grades 1 to 12, inclusive, school.
(3) Housing subject to rent or price control through a public entity’s valid exercise of its police power consistent with Chapter 2.7 (commencing with Section 1954.50) that restricts annual increases in the rental rate to an amount less than that provided in subdivision (a).
(4) Housing that has been issued a certificate of occupancy within the previous 15 years, unless the housing is a mobilehome.
(5) Residential real property that is alienable separate from the title to any other dwelling unit, including a mobilehome, provided that both of the following apply:
(A) The owner is not any of the following: (i) A real estate investment trust, as defined in Section 856 of the Internal Revenue Code.
(ii) A corporation. (iii) A limited liability company in which at least one member is a corporation.
(iv) Management of a mobilehome park, as defined in Section 798.2. (B) (i) The tenants have been provided written notice that the residential real property is exempt from this section using the following statement:
“This property is not subject to the rent limits imposed by Section 1947.12 of the Civil Code and is not subject to the just cause requirements of Section 1946.2 of the Civil Code. This property meets the requirements of Sections 1947.12 (d)(5) and 1946.2 (e)(8) of the Civil Code and the owner is not any of the following: (1) a real estate investment trust, as defined by Section 856 of the Internal Revenue Code; (2) a corporation; or (3) a limited liability company in which at least one member is a corporation.”
88
Ch. 290 — 18 —
(ii) For a tenancy existing before July 1, 2020, or July 1, 2022, if the lease is for a tenancy in a mobilehome, the notice required under clause (i) may, but is not required to, be provided in the rental agreement.
(iii) For a tenancy commenced or renewed on or after July 1, 2020, or July 1, 2022, if the lease is for a tenancy in a mobilehome, the notice required under clause (i) must be provided in the rental agreement.
(iv) Addition of a provision containing the notice required under clause (i) to any new or renewed rental agreement or fixed-term lease constitutes a similar provision for the purposes of subparagraph (E) of paragraph (1) of subdivision (b) of Section 1946.2.
(6) A property containing two separate dwelling units within a single structure in which the owner occupied one of the units as the owner’s principal place of residence at the beginning of the tenancy, so long as the owner continues in occupancy, and neither unit is an accessory dwelling unit or a junior accessory dwelling unit.
CRC § 25.4 Medium relevance — show source text
@48|4@48| |140|119|110|8|4@43|4@34|4@48|4@48|4@48|4@48|4@48|4@48| |140|119|110|9|4@34|4@34|4@48|4@48|4@48|4@48|4@48|4@48| |140|119|110|10|4@34|4@31|4@48|4@48|4@48|4@48|4@48|4@48| |150|127|117|8|4@37|4@34|4@48|4@48|4@48|4@48|4@48|4@48| |150|127|117|9|4@34|4@33|4@48|4@48|4@48|4@48|4@48|4@48| |150|127|117|10|4@31|4@27|4@48|4@48|4@48|4@48|4@48|4@48| |160|136|125|8|4@34|4@34|4@48|4@48|4@48|4@48|4@48|4@48| |160|136|125|9|4@34|4@29|4@48|4@48|4@48|4@48|4@48|4@48| |160|136|125|10|4@27|4@24|4@48|4@48|4@48|4@48|4@48|4@48| |For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 mile per hour = 0.447 m/s, 1 pound per square inch = 1.895 kPa, 1 square foot = 0.0929 m2.
a. Table is based on ASCE 7 components and cladding wind pressures for an enclosed building using a mean roof height of 35 feet, interior wall area 4, an effective wind area of
10 square feet, topographic factor,Kzt, equal to 1.0, and Risk Category II.
b. Table is based on concrete with a minimum specified compressive strength of 2,500 psi.
c. See Section R608.6.5 for location of reinforcement in wall.
d. Deflection criterion is_L_/240, where_L_ is the unsupported height of the wall in inches.
e. Interpolation is not permitted.
f. Where No. 4 reinforcing bars at a spacing of 48 inches are specified in the table as indicated by shaded cells, use of bars with a minimum yield strength of 40,000 psi or 60,000
psi is permitted.
g. Other than for No.CRC § 932.3 Medium relevance — show source text
Evaporative coolers. . . . . . . . . . . . . . . . . . . . . . . . 932.3
Fire and smoke dampers . . . . . . . . . . . . . . . . . . . 606.8
Floor furnace. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 906.9
Fuel gas meters . . . . . . . . . . . . . . . . . 1308.5.1, D 104.2
Fuel gas piping . . . . . . . . . . . . . . . . . . . . . . . 1310.3.3.1
Fuel gas pressure regulators . . . . . . . . . . . . . .1308.6.2,
1310.5.1
Grease filters. . . . . . . . . . . . . . . . . . . . . . . . . . 509.2.3.2
Lapped flanges . . . . . . . . . . . . . . . . . . . . . . . 1308.4.9.6
Motors and fans, exhaust systems . . . . . . . . . . . . 503.1
Refrigeration equipment . . . . . . . . . . . . . . . . . . . 1105.3
ACCESSIBLE
Definition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203.0
Easily, definition. . . . . . . . . . . . . . . . . . . . . . . . . . . 207.0
Readily, definition . . . . . . . . . . . . . . . . . . . . . . . . . 203.0
ACCESSORY DWELLING UNIT
Definition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203.0
ADMINISTRATION
California . . . . . . . . . . . . . . . . . . . . Chapter 1, Division I
General . . . . . . . . . . . . . . . . . . . . . Chapter 1 , Division II
AIR
Balancing . . . . . . . . . . . . . 314.0, 403.10, 407.3, 511.3.1,
E 503.3.1, E 503.6.5.3,
E 605.1.5, E 803.2
Circulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 407.4
Classification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 403.9
Combustion . . . . . . . . . . . . . . . . . (see Combustion Air)
Dilution . . . . . . . . . . . . . . . . . . . . . . . 203.0, Table 403.7,
701.1, 701.1.1, 701.8, 701.10,
Frequently asked questions
How do I tell whether a rented room is a "dwelling unit"?
If the room has permanent provisions for living, sleeping, eating, cooking and sanitation it meets the dwelling‑unit definition; if any of those permanent facilities (especially cooking and sanitation) are missing, it is not a full dwelling unit under the code.
Are ADUs always considered separate dwelling units?
Yes — an Accessory Dwelling Unit is defined in § R202 as a residential dwelling unit with complete independent living facilities; state ADU laws and local ordinances can impose additional requirements but do not change that it’s a dwelling unit for code purposes.
If a building has three units, is it still a "dwelling"?
No — the code’s short form dwelling definition applies to buildings that contain one or two dwelling units. Buildings with three or more units fall outside that narrow label and are treated under the multifamily provisions.
Where do I look if the CRC doesn’t define the term I need?
Check § R201.3 — the CRC defaults to definitions in the California Building Standards Code (Title 24) when CRC Chapter 2 does not define a term.
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