Title 24 · California Energy Code

When can a mixed-occupancy building be designed to one occupancy's rules (80% / 90% exceptions)?

Q: When do I count an area as “conditioned floor area” vs “unconditioned”?

Count an area as conditioned if it is served by the building’s heating or cooling system and maintained within conditioned space temperature ranges per the code definitions; otherwise count it as unconditioned . The code’s definitions and rules of construction (see § 100.1 ) control precise definitions.

If one occupancy makes up at least 80% of a building’s conditioned area you may design the whole building’s envelope, HVAC and water heating to that occupancy’s Part 6 rules (but you must still meet per-space lighting and mandatory measures). If one occupancy makes up at least 90% of the combined conditioned + unconditioned area you may apply that occupancy’s indoor lighting rules buildingwide. These allowances and their limits are in § 100.0(f) and its two exceptions.

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Last reviewed: July 6, 2026

What the code requires — 2-4 sentences

Under § 100.0(f) a mixed occupancy building must have the space for each occupancy comply with the Part 6 requirements applicable to that occupancy. § 100.0(f) also provides two limited exceptions that allow designing some or all systems for the building using the rules for a single dominant occupancy when that occupancy meets specified area thresholds.

If one occupancy occupies most of the building, you may treat the whole building like that occupancy for certain systems — but only when the 80% or 90% area tests in the exceptions are met and the listed per-space mandatory measures and lighting rules remain satisfied.

Requirements in detail

Core rule (what normally applies)

Default requirement: each portion of a mixed-occupancy building must meet the Part 6 provisions for its own occupancy. This is the baseline that applies unless an exception is met. § 100.0(f).

The two exceptions (what they allow and when)

Exception 1 — 80% conditioned-floor-area test
- If one occupancy constitutes at least 80 percent of the conditioned floor area of the building, then the entire building envelope, HVAC, and water heating may be designed to the Part 6 provisions for that dominant occupancy. However, the applicable lighting requirements (Sections § 140.6–§ 140.8, § 150.0(k), § 160.5, § 170.2(e)) and the mandatory measures (Sections § 110.0–§ 130.5, § 150.0, § 160.0–§ 160.9) still must be met for each occupancy and space. (Exception 1 to § 100.0(f)).
Exception 2 — 90% combined-area test (lighting only)
- If one occupancy constitutes at least 90 percent of the combined conditioned plus unconditioned floor area of the building, then the entire building indoor lighting may be designed to the lighting provisions for that dominant occupancy. (Exception 2 to § 100.0(f)).

Decision table — what to check and where to apply the single-occupancy rules

Decision dimension	Threshold / value to meet	What can be designed to single-occupancy rules	Code Reference
Conditioned floor area proportion	≥ 80% of conditioned floor area	Envelope, HVAC, water heating may follow dominant occupancy rules (lighting & mandatory measures still apply per space)	§ 100.0(f) — Exception 1
Combined conditioned + unconditioned floor area proportion	≥ 90% of (conditioned + unconditioned) floor area	Indoor lighting for entire building may follow dominant occupancy rules	§ 100.0(f) — Exception 2
Lighting & mandatory measures	N/A (applies regardless)	Lighting sections § 140.6–§ 140.8, § 150.0(k), § 160.5, § 170.2(e) and mandatory measures § 110.0–§ 130.5, § 150.0, § 160.0–§ 160.9 must be met for each occupancy/space even when exceptions are used	Exception 1 text in § 100.0(f)

Notes on table terms (first mention bolded): conditioned floor area, unconditioned floor area, envelope, HVAC, water heating, indoor lighting.

Exceptions & special cases

Lighting is treated separately: even if Exception 1 is met and envelope/HVAC/water heating are treated as a single occupancy, lighting rules still must be satisfied for each occupancy/space as listed in the exception text. Do not assume Exception 1 lets you ignore per-space lighting requirements.
Exception 2 covers only indoor lighting and uses a different area base (conditioned + unconditioned) with a higher threshold (90%). It does not permit treating envelope, HVAC, or water heating to single-occupancy rules.
The exceptions are permissive: they allow you to design certain systems to a single occupancy’s rules; they do not require you to use the exception if you prefer to design each portion to its own occupancy rules. § 100.0(f).

Common mistakes

Failing to use the correct area basis:
- For Exception 1 use conditioned floor area only; for Exception 2 use conditioned + unconditioned floor area. Mixing these bases leads to incorrect qualification.
Assuming Exception 1 includes lighting — it does not. Exception 1 explicitly preserves per-space lighting and mandatory measures obligations.
Counting gross building area, rentable area, or excluded areas (e.g., roofs, exterior parking not part of the floor area measure) without confirming they qualify as conditioned or unconditioned floor area per applicable definitions. The code’s definitions and rules of construction (Section § 100.1) determine what counts as conditioned/unconditioned.
Overlooking mandatory measures: even when envelope/HVAC/water heating are designed to the dominant occupancy, mandatory measures in §§ 110.0–130.5, 150.0, and 160.0–160.9 still must be met for each occupancy and space.

Worked example — concrete scenario

Scenario: a 10,000 ft² mixed-use building with both conditioned and unconditioned space.

Conditioned floor area:
- Residential apartments (dominant occupancy): 6,700 ft² (conditioned)
- Retail tenant (other occupancy): 1,300 ft² (conditioned)
- Total conditioned = 8,000 ft²
Unconditioned area:
- Parking / storage (unconditioned): 2,000 ft²
Compute tests:
- Conditioned-area share for residential = 6,700 / 8,000 = 83.75% → meets the 80% conditioned-area test. Therefore Exception 1 may be used to design the entire building envelope, HVAC, and water heating to the residential (dominant) occupancy rules — but the lighting rules and mandatory measures still must be met for the retail space and each residential space. Cite: Exception 1 to § 100.0(f).
- Combined conditioned + unconditioned area = 8,000 + 2,000 = 10,000 ft². Residential share of the combined area = 6,700 / 10,000 = 67% → does not meet the 90% combined-area test, so Exception 2 cannot be used; indoor lighting cannot be designed solely to the residential lighting rules for the whole building. Cite: Exception 2 to § 100.0(f).
Practical outcome for this scenario:
- You may design the building envelope, HVAC and water heating according to residential Part 6 rules (Exception 1) provided you still comply with per-space lighting (retail must meet its lighting requirements) and mandatory measures for each occupancy. You may NOT apply residential-only lighting rules buildingwide because Exception 2’s 90% combined-area threshold is not met.

Related provisions

§ 100.0(f) — Mixed occupancy general rule (baseline).
§ 100.0(f) — Exception 1 — 80% conditioned floor area test (envelope, HVAC, water heating).
§ 100.0(f) — Exception 2 — 90% combined conditioned + unconditioned area test (indoor lighting).
Lighting and PV references cited within the exceptions and adjacent rules: § 140.6–§ 140.8, § 140.10, § 150.0(k), § 160.5, § 170.2(e) (see Exception 1 wording).
Mandatory measures referenced: § 110.0–§ 130.5, § 150.0, § 160.0–§ 160.9 (these must be met for each occupancy/space even when an exception is used).

Code references

Grounded in the retrieved California Energy Code — click a citation to read the verbatim passage:

§ 150.2 High relevance — show source text
For alterations that change the occupancy classification of the building, the requirements specified in Section 150.2 apply to the occupancy after the alterations. C. Multifamily buildings. Section 180.0 applies to new construction in existing multifamily buildings. New construction in existing buildings includes additions, alterations and repairs. Section 180.0 specifies requirements that uniquely apply to additions, alterations or repairs to existing buildings, and specifies which requirements in other sections also apply. For alterations that change the occupancy classification of the building, the requirements specified in Section 180.0 apply to the occupancy after the alterations. 4. Installation of insulation in existing buildings. Section 110.8(d) applies to buildings in which insulation is being installed in existing attics, or on existing water heaters or existing space conditioning ducts. 5. Outdoor lighting. Sections 110.9, 130.0, 130.2, 130.4, 140.7, and 150.0 apply to newly constructed outdoor lighting systems, and Section 141.0 applies to outdoor lighting that is either added or altered. 6. Signs. Sections 130.0, 130.3 and 140.8 apply to newly constructed signs located either indoors or outdoors, and Section 141.0 applies to sign alterations located either indoors or outdoors.

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ALL OCCUPANCIES—GENERAL PROVISIONS

(f) Mixed occupancy. When a building is designed and constructed for more than one type of occupancy (residential and nonresidential), the space for each occupancy shall meet the provisions of Part 6 applicable to that occupancy.

Exception 1 to Section 100.0(f): If one occupancy constitutes at least 80 percent of the conditioned floor area of the building, the entire building envelope, HVAC and water heating may be designed to comply with the provisions of Part 6 applicable to that occupancy, provided that the applicable lighting requirements in Sections 140.6 through 140.8, 150.0(k), or 160.5 and 170.2(e) are met for each occupancy and space, and mandatory measures in Sections 110.0 through 130.5, 150.0, and 160.0 through 160.9 are met for each occupancy and space.

Exception 2 to Section 100.0(f): If one occupancy constitutes at least 90 percent of the combined conditioned plus unconditioned floor area of the building, the entire building indoor lighting may be designed to comply with only the lighting provisions of Part 6 applicable to that occupancy.

(g) Administrative requirements. Administrative requirements relating to permit requirements, enforcement by the Commission, locally adopted energy standards, interpretations, claims of exemption, approved calculation methods, rights of appeal, and certification and labeling requirements of fenestration products and roofing products are specified in California Code of Regulations, Title 24, Part 1, Sections 10-101 to 10-114.

(h) Certification requirements for manufactured equipment, products and devices. Part 6 limits the installation of manufactured equipment, products and devices to those that have been certified as specified by Sections 110.0 and 110.1. Requirements for manufactured equipment, products, and devices, when not specified in Title 24 Part 6, are specified in California Code of Regulations, Title 20, Sections 1601–1609.
§ 1006.3.4.1 High relevance — show source text
1006.3.4.1 Mixed occupancies. Where one exit, or exit access stairway or ramp providing access to exits at other stories, is permitted to serve individual stories, mixed occupancies shall be permitted to be served by single exits provided that each individual occupancy complies with the applicable requirements of Table 1006.3.4(1) or 1006.3.4(2) for that occupancy. Where applicable, cumulative occupant loads from adjacent occupancies shall be considered to be in accordance with the provisions of Section 1004.1. In each story of a mixed occupancy building, the maximum number of occupants served by a single exit shall be such that the sum of the ratios of the calculated number of occupants of the space divided by the allowable number of occupants indicated in Table 1006.3.4(2) for each occupancy does not exceed one. Where dwelling units are located on a story with other occupancies, the actual number of dwelling units divided by four plus the ratio from the other occupancy does not exceed one.

SECTION 1007—EXIT AND EXIT ACCESS DOORWAY CONFIGURATION

1007.1 General. Exits, exit access doorways, and exit access stairways and ramps serving spaces, including individual building stories, shall be separated in accordance with the provisions of this section.

1007.1.1 Two exits or exit access doorways. Where two exits, exit access doorways, exit access stairways or ramps, or any combination thereof, are required from any portion of the exit access, they shall be placed a distance apart equal to not less than one-half of the length of the maximum overall diagonal dimension of the building or area to be served measured in a straight line between them. Interlocking or scissor stairways shall be counted as one exit stairway.

Exceptions:
1. Where interior exit stairways or ramps are interconnected by a 1-hour fire-resistance-rated corridor conforming to the requirements of Section 1020, the required exit separation shall be measured along the shortest direct line of travel within the corridor.
2. Where a building is equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 or 903.3.1.2, the separation distance shall be not less than one-third of the length of the maximum overall diagonal dimension of the area served.
1007.1.1.1 Measurement point. The separation distance required in Section 1007.1.1 shall be measured in accordance with the following:
1. The separation distance to exit or exit access doorways shall be measured to any point along the width of the doorway.
2. The separation distance to exit access stairways shall be measured to the closest riser.
3. The separation distance to exit access ramps shall be measured to the start of the ramp run.
1007.1.2 Three or more exits or exit access doorways. Where access to three or more exits is required, not less than two exit or exit access doorways shall be arranged in accordance with the provisions of Section 1007.1.1. Additional required exit or exit access doorways shall be arranged a reasonable distance apart so that if one becomes blocked, the others will be available.

1007.1.3 Remoteness of exit access stairways or ramps. Where two exit access stairways or ramps provide the required means of egress to exits at another story, the required separation distance shall be maintained for all portions of such exit access stair ways or ramps.
§ 903.3.1.1 High relevance — show source text
Exceptions:
1. The occupancy located on an occupiable roof shall not be limited to the occupancies allowed on the story immediately below the roof where the building is equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 or 903.3.1.2 and occupant notification in accordance with Sections 907.5.2.1 and 907.5.2.3 is provided in the area of the occupiable roof. Emergency voice/alarm communication system notification per Section 907.5.2.2 shall also be provided in the area of the occupiable roof where such system is required elsewhere in the building.
2. Assembly occupancies shall be permitted on roofs of open parking spaces of Type I or Type II construction, in accordance with the exception to Section 903.2.1.6.
503.1.4.1 Enclosures over occupiable roof areas. Elements or structures enclosing the occupiable roof areas shall not extend more than 48 inches (1220 mm) above the surface of the occupiable roof.

Exceptions:
1. Penthouses constructed in accordance with Section 1511.2 and towers, domes, spires and cupolas constructed in accordance with Section 1511.5.
2. Elements or structures enclosing the occupiable roof areas where the roof deck is located more than 75 feet (22 860 mm) above the lowest level of fire department vehicle access.
SECTION 504—BUILDING HEIGHT AND NUMBER OF STORIES

504.1 General. The height, in feet, and the number of stories of a building shall be determined based on the type of construction, occupancy classification and whether there is an automatic sprinkler system installed throughout the building.

Exception: The building height of one-story aircraft hangars, aircraft paint hangars and buildings used for the manufacturing of aircraft shall not be limited where the building is provided with an automatic sprinkler system or automatic fire-extinguishing system in accordance with Chapter 9 and is entirely surrounded by public ways or yards not less in width than one and one-half times the building height.

504.1.1 Unlimited area buildings. The height of unlimited area buildings shall be designed in accordance with Section 507.

504.1.2 Special provisions. The special provisions of Section 510 permit the use of special conditions that are exempt from, or modify, the specific requirements of this chapter regarding the allowable heights of buildings based on the occupancy classification and type of construction, provided the special condition complies with the provisions specified in Section 510.

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GENERAL BUILDING HEIGHTS AND AREAS

504.2 Mixed occupancy. In a building containing mixed occupancies in accordance with Section 508, no individual occupancy shall exceed the height and number of story limits specified in this section for the applicable occupancies.

504.3 Height in feet. The maximum height, in feet, of a building shall not exceed the limits specified in Table 504.3.

Exception: Towers, spires, steeples and other rooftop structures shall be constructed of materials consistent with the required type of construction of the building except where other construction is permitted by Section 1511.2.4. Such structures shall not be used for habitation or storage. The structures shall be unlimited in height where of noncombustible materials and shall not extend more than 20 feet (6096 mm) above the allowable building height where of combustible materials (see Chapter 15 for additional requirements).

|TABLE 504.
§ 100.0 High relevance — show source text
Exception 1 to Section 100.0(f): If one occupancy constitutes at least 80 percent of the conditioned floor area of the building, the entire building envelope, HVAC and water heating may be designed to comply with the provisions of Part 6 applicable to that occupancy, provided that the applicable lighting requirements in Sections 140.6 through 140.8, 150.0(k), or 160.5 and 170.2(e) are met for each occupancy and space, and mandatory measures in Sections 110.0 through 130.5, 150.0, and 160.0 through 160.9 are met for each occupancy and space.

Exception 2 to Section 100.0(f): If one occupancy constitutes at least 90 percent of the combined conditioned plus unconditioned floor area of the building, the entire building indoor lighting may be designed to comply with only the lighting provisions of Part 6 applicable to that occupancy.

(g) Administrative requirements. Administrative requirements relating to permit requirements, enforcement by the Commission, locally adopted energy standards, interpretations, claims of exemption, approved calculation methods, rights of appeal, and certification and labeling requirements of fenestration products and roofing products are specified in California Code of Regulations, Title 24, Part 1, Sections 10-101 to 10-114.

(h) Certification requirements for manufactured equipment, products and devices. Part 6 limits the installation of manufactured equipment, products and devices to those that have been certified as specified by Sections 110.0 and 110.1. Requirements for manufactured equipment, products, and devices, when not specified in Title 24 Part 6, are specified in California Code of Regulations, Title 20, Sections 1601–1609.

Note: Authority: Sections 25213, 25218, 25218.5, 25402 and 25402.1, Public Resources Code . Reference: Sections 25007, 25008, 25218.5, 25310, 25402, 25402.1, 25402.4, 25402.5, 25402.8, and 25943, Public Resources Code .

SECTION 100.1 — DEFINITIONS AND RULES OF CONSTRUCTION

(a) Rules of Construction.
1. Where the context requires, the singular includes the plural and the plural includes the singular.
2. The use of “and” in a conjunctive provision means that all elements in the provision must be complied with or must exist to make the provision applicable. Where compliance with one or more elements suffices, or where existence of one or more elements makes the provision applicable, “or” (rather than “and/or”) is used.
3. “Shall” is mandatory and “may” is permissive.
(b) Definitions. Terms, phrases, words and their derivatives in Part 6 shall be defined as specified in Section 100.1. Terms, phrases, words and their derivatives not found in Section 100.1 shall be defined as specified in the “Definitions” chapters of Title 24, Parts 1 through 5 of the California Code of Regulations. Where terms, phrases, words and their derivatives are not defined in any of the references above, they shall be defined as specified in Webster’s Third New International Dictionary of the English Language, Unabridged (1961 edition, through the 2002 addenda), unless the context requires otherwise.
§ 301.3.2 High relevance — show source text
301.3.2 Waste diversion. The requirements of Section 5.408 shall be required for additions and alterations whenever a permit is required for work.

301.4 Mandatory measures for public schools and community colleges. [DSA-SS] New building construction and site work on a new or existing site shall comply with Section 301.4.

301.4.1 Building and site construction on a new site shall comply with Chapter 5 as adopted by DSA-SS.

301.4.2 Work on an existing site shall comply with Section 301.4.2.

301.4.2.1 Newly constructed site work shall comply with Chapter 5 as adopted by DSA-SS.

301.4.2.2 Newly constructed buildings shall comply with Chapter 5 as adopted by DSA-SS and Section 301.4.3.

301.4.2.3 Additions to existing buildings shall comply with Section 301.4.3.

301.4.2.4 Rehabilitated landscape areas shall comply with Sections 5.304.6 and 5.106.12.

301.4.2.5 Alterations and additions to existing parking facilities shall comply with Section 5.106.5.6.4. Additions to existing parking facilities shall comply with Section 5.106.12.

301.4.2.6 Alterations and additions to existing buildings shall comply with Sections 5.105.1, 5.106.5.6.5, 5.409, and 5.506.3.

301.4.3 Minimum rehabilitated landscape area requirement. A minimum rehabilitated landscape area equal to 75 percent of the footprint area of the building shall comply with Section 5.304.6 and Section 5.106.12. New buildings or additions to existing buildings less than 1,600 square feet shall not be required to comply with Section 301.4.3.

301.5 Health Facilities. [OSHPD 1, 2 & 4] Health facilities under the jurisdiction of the Office of Statewide Health Planning and Development (OSHPD) are required to comply with the mandatory measures prescribed in Section 5.304, Outdoor Water Use. Compliance with Section 5.304, as adopted by the Building Standards Commission, is enforced by the local agency having jurisdiction. Evidence of local approval shall be submitted to OSHPD prior to issuance of plan approval or a building permit.

2025 CALIFORNIA GREEN BUILDING STANDARDS CODE 3-3

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GREEN BUILDING

SECTION 302—MIXED OCCUPANCY BUILDINGS

302.1 Mixed occupancy buildings. In mixed occupancy buildings, each portion of a building shall comply with the specific green building measures applicable to each specific occupancy.

Exceptions:
1. [HCD] Accessory structures and accessory occupancies serving residential buildings shall comply with Chapter 4 and Appendix A4, as applicable.
2. [HCD] For the purposes of CALGreen, live/work units, complying with Section 508.5 of the California Building Code, shall not be considered mixed occupancies. Live/work units shall comply with Chapter 4 and Appendix A4, as applicable.
SECTION 303—PHASED PROJECTS
§ 5-14 High relevance — show source text
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GENERAL BUILDING HEIGHTS AND AREAS

507.9 Unlimited mixed occupancy buildings with Group H-5. The area of a Group B, F, H-5, M or S building not more than two stories above grade plane shall not be limited where the building is equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1, and is surrounded and adjoined by public ways or yards not less than 60 feet (18 288 mm) in width, provided that the following criteria are met:
1. Buildings containing Group H-5 occupancy shall be of Type I or II construction.
2. Each area used for Group H-5 occupancy shall be separated from other occupancies as required in Sections 415.11 and 508.4.
3. Each area used for Group H-5 occupancy shall not exceed the maximum allowable area permitted for such occupancies in Section 503.1 including modifications of Section 506. Exception: Where the Group H-5 occupancy exceeds the maximum allowable area, the Group H-5 shall be subdivided into areas that are separated by 2-hour fire barriers.
507.10 Aircraft paint hangar. The area of a Group H-2 aircraft paint hangar not more than one story above grade plane shall not be limited where such aircraft paint hangar complies with the provisions of Section 412.5 and is surrounded and adjoined by public ways or yards not less in width than one and one-half times the building height.

507.11 Group E buildings. The area of a Group E building not more than one story above grade plane, of Type II, IIIA or IV construction, shall not be limited provided that the following criteria are met:
1. Each classroom shall have not less than two means of egress, with one of the means of egress being a direct exit to the outside of the building complying with Section 1022.
2. The building is equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1.
3. The building is surrounded and adjoined by public ways or yards not less than 60 feet (18 288 mm) in width.
507.12 Motion picture theaters. In buildings of Type II construction, the area of a motion picture theater located on the first story above grade plane shall not be limited where the building is provided with an automatic sprinkler system throughout in accordance with Section 903.3.1.1 and is surrounded and adjoined by public ways or yards not less than 60 feet (18 288 mm) in width.

507.13 Covered and open mall buildings and anchor buildings. The area of covered and open mall buildings and anchor buildings not exceeding three stories in height that comply with Section 402 shall not be limited.

SECTION 508—MIXED USE AND OCCUPANCY

508.1 General. Each portion of a building shall be individually classified in accordance with Section 302.1. Where a building contains more than one occupancy group, the building or portion thereof shall comply with the applicable provisions of Section 508.2, 508.3, 508.4 or 508.5, or a combination of these sections.

Exceptions:
1. Occupancies separated in accordance with Section 510.
2. Where required by Table 415.6.5, areas of Group H-1, H-2 and H-3 occupancies shall be located in a detached building or structure.
§ 18001.8. High relevance — show source text
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.

d. A high-rise structure, as defined in subdivision (b) of Section 13210 and regulated by Chapter 3 (commencing with Section 13210), and which is used for purposes other than as dwelling units intended for human occupancy, is exempt from the requirements of this section. e. The owner shall be responsible for testing and maintaining detectors in hotels, motels, lodging houses and common stair- wells of apartment complexes and other multiple-dwelling complexes. An owner or the owner’s agent may enter any dwelling unit, efficiency dwelling unit, guest room and suite owned by the owner for the purpose of installing, repairing, testing and maintaining single station smoke detectors required by this section. Except in cases of emergency, the owner or owner’s agent shall give the tenants of each such unit, room or suite reasonable notice in writing of the intention to enter and shall enter only during normal business hours. Twenty-four hours shall be presumed to be reasonable notice in absence of evidence to the contrary. The smoke detector shall be operable at the time that the tenant takes possession. The apartment complex tenant shall be responsible for notifying the manager or owner if the tenant becomes aware of an inoperable smoke detector within his or her unit. The owner or authorized agent shall correct any reported deficiencies in the smoke detector and shall not be in violation of this section for a deficient smoke detector when he or she has not received notice of the deficiency. f. A violation of this section is an infraction punishable by a maximum fine of two hundred dollars ($200) for each offense. g. This section shall not affect any rights which the parties may have under any other provision of law because of the presence or absence of a smoke detector.

3-56 2025 CALIFORNIA RESIDENTIAL CODE
§ 1606.4 High relevance — show source text
1606.4 Photovoltaic, Building-Integrated (BIPV) Roof Covering 1505.8, Tables 1507.1.1(1)–1507.1.1(3), 1507.16, 1512 Photovoltaic, Building-Integrated (BIPV) Roof Panel 1505.8, 1507.17, 1512 Photovoltaic, Building-Integrated (BIPV) System 1505.8, 1512 Photovoltaic (PV) Module 1505.8, 1511.10, 1511.10.1, 1603.1.8.1, 1606.4, 1607.14.3.2 Photovoltaic (PV) Panel 1505.8, 1511.10, 1511.10.1, 1603.1.8.1, 1606.4, 1607.14.3.2 Photovoltaic (PV) Panel System, Ground Mounted 1604.5.2, 1607.14.3.4, 3111.3.6 Photovoltaic (PV) Support Structure, Elevated 1604.5.2, 1607.14.3.3, 3111.3.5 Photovoltaic Panel Systems 1604.5.2, 1607.14.3, 1613.4

Certificates (see Certificate of Occupancy) Change (see Change of Occupancy) Floor loads Table 1607.1 Height in mixed occupancy buildings 504.2

Roofs

Special Chapter 4 Occupancy Classification Chapter 3 Covered and open mall buildings 402

Detailed requirements Chapter 4 Exceptions 303.1.1, 303.1.4, 305.1.1, 305.2.1, 305.2.3, 307.1.1, 308.5.1, 308.5.4, 310.4.1, 311.1.1

HPM 415.11

Mixed 508, 510 Occupied roofs 302.1, 503.1.4 Occupancy Separation Accessory 508.2 Aircraft related 412.4.1 Nonseparated use method 508.3 Separated use method 508.4 Special provisions 510 Unlimited area buildings 507.1.1, 507.4.1, 507.8 Occupant Evacuation Elevators 403.5.2, 403.6.2, 3008 Occupant Load Business Table 1004.5, 1004.8 Calculated 1004.5 Certificate of occupancy 111 Covered and open mall building 402.8.2

Cumulative 1004.2

Increased 1004.5.1 Multiple function 1004.3 Multiple occupancies 1004.4 Outdoors 1004.7 Seating, fixed 1004.6 Signs 1004.9 Occupiable Roofs 503.1.4, 1004.7, 1006.3, 1009.2.1, 1607.14.2 Office Buildings (see Group B Occupancies) Classification 304
§ 110.10 High relevance — show source text
Install alternative plumbing piping to permit the discharge from the clothes washer and all showers and bathtubs to be used for an irrigation system in compliance with the California Plumbing Code and any applicable local ordinances; or iv. Install a rainwater catchment system designed to comply with the California Plumbing Code and any applicable local ordinances, and that uses rainwater flowing from at least 65 percent of the available roof area.

B. Multifamily buildings, hotel/motel occupancies and nonresidential buildings. The solar zone shall be located on the roof or overhang of the building or on the roof or overhang of another structure located within 250 feet of the building or on covered parking installed with the building project, and shall have a total area no less than 15 percent of the total roof area of the building excluding any skylight area. The solar zone requirement is applicable to the entire building, including mixed occupancy.

Exception 1 to Section 110.10(b)1B: High-rise multifamily buildings, hotel/motel occupancies, and nonresidential buildings with a permanently installed solar electric system having a nameplate DC power rating, measured under Standard Test Conditions, of no less than one watt per square foot of roof area.

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on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

ALL OCCUPANCIES—MANDATORY REQUIREMENTS FOR THE MANUFACTURE, CONSTRUCTION AND INSTALLATION OF SYSTEMS, EQUIPMENT AND BUILDING COMPONENTS

Exception 2 to Section 110.10(b)1B: High-rise multifamily buildings, hotel/motel occupancies with a permanently installed domestic solar water-heating system complying with Section 150.1(c)8Biii.

Exception 3 to Section 110.10(b)1B: Buildings with a designated solar zone area that is no less than 50 percent of the potential solar zone area. The potential solar zone area is the total area of any low-sloped roofs where the annual solar access is 70 percent or greater and any steep-sloped roofs oriented between 90 degrees and 300 degrees of true north where the annual solar access is 70 percent or greater. Solar access is the ratio of solar insolation including shade to the solar insolation without shade. Shading from obstructions located on the roof or any other part of the building shall not be included in the determination of annual solar access.

Exception 4 to Section 110.10(b)1B: Low-rise and high-rise multifamily buildings with all thermostats in each dwelling unit are demand response controls that comply with Section 110.12(a), and are capable of receiving and responding to Demand Response Signals prior to granting of an occupancy permit by the enforcing agency. In addition, either A or B below:

A. In each dwelling unit, comply with one of the following measures: i. Install a dishwasher that meets or exceeds the ENERGY STAR Program requirements with either a refrigerator that meets or exceeds the ENERGY STAR Program requirements or a whole house fan driven by an electronically commutated motor; or ii. Install a home automation system that complies with Section 110.12(a) and is capable of, at a minimum, controlling the appliances and lighting of the dwelling and responding to demand response signals; or iii. Install alternative plumbing piping to permit the discharge from the clothes washer and all showers and bathtubs to be used for an irrigation system in compliance with the California Plumbing Code and any applicable local ordinances; or iv.
§ 17958.5 High relevance — show source text
Amendments, additions and deletions to this code adopted by a city, county, or city and county_ pursuant to California Health and Safety Code Sections 17958.5, 17958.7 and 18941.5, together with all applicable portions of this code, shall also become effective 180 days after publication of the California Building Standards Code by the California Building Standards Commission.

1.8.6.2 Findings, filings and rejections of local modifications. Prior to making any modifications or establishing more restrictive building standards, the governing body shall make express findings and filings, as required by California Health and Safety Code Section 17958.7, showing that such modifications are reasonably necessary due to local climatic, geological or topographical conditions. No modification shall become effective or operative unless the following requirements are met: 1. The express findings shall be made available as a public record. 2. A copy of the modification and express finding, each document marked to cross-reference the other, shall be filed with the California Building Standards Commission for a city, county, or city and county and with the Department of Housing and Community Development for fire protection districts. 3. The California Building Standards Commission has not rejected the modification or change.

Nothing in this section shall limit the authority of fire protection districts pursuant to California Health and Safety Code Section 13869.7(a).

SECTION 1.8.7—ALTERNATE MATERIALS, DESIGNS, TESTS AND METHODS OF CONSTRUCTION

1.8.7.1 General. The provisions of this code, as adopted by the Department of Housing and Community Development are not intended to prevent the use of any alternate material, appliance, installation, device, arrangement, design or method of construction not specifically prescribed by this code. Consideration and approval of alternates shall comply with Section 1.8.7.2 for local building departments and Section 1.8.7.3 for the Department of Housing and Community Development.

1.8.7.2 Local building departments. The building department of any city, county, or city and county may approve alternates for use in the erection, construction, reconstruction, movement, enlargement, conversion, alteration, repair, removal, demolition or arrangement of apartments, condominiums, hotels, motels, lodging houses, dwellings or accessory structures, except for the following: 1. Structures located in mobilehome parks as defined in California Health and Safety Code Section 18214. 2. Structures located in special occupancy parks as defined in California Health and Safety Code Section 18862.43. 3. Factory-built housing as defined in California Health and Safety Code Section 19971.

1.8.7.2.1 Approval of alternates. The consideration and approval of alternates by a local building department shall comply with the following procedures and limitations: 1. The approval shall be granted on a case-by-case basis. 2. Evidence shall be submitted to substantiate claims that the proposed alternate, in performance, safety and protection of life and health, conforms to, or is at least equivalent to, the standards contained in this code and other rules and regulations promulgated by the Department of Housing and Community Development. 3. The local building department may require tests performed by an approved testing agency at the expense of the owner or owner’s agent as proof of compliance. _4.
§ 1.5.2 High relevance — show source text
1.5.2_||||X|||||||||||||||||||| |R109.1.5.3||||X|||||||||||||||||||| |R109.1.6|||X|X|||||||||||||||||||| |R109.1.6.1||||X|||||||||||||||||||| |R109.1.6.2||||X|||||||||||||||||||| |R109.2 - R109.4|||X||||||||||||||||||||| |R110 - R110.4|||X||||||||||||||||||||| |R111 - R111.3|||X||||||||||||||||||||| |R113.1 - R113.2|||X||||||||||||||||||||| |R114.1 - R114.4|||X|||||||||||||||||||||

The state agency does not adopt sections identified with the following symbol: †

1-2 2025 CALIFORNIA RESIDENTIAL CODE

on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

PART I—ADMINISTRATIVE

1 ADMINISTRATION

DIVISION I CALIFORNIA ADMINISTRATION

SECTION 1.1—GENERAL

1.1.1 Title. These regulations shall be known as the California Residential Code, may be cited as such and will be referred to herein as “this code.” The California Residential Code is Part 2.5 of thirteen parts of the official compilation and publication of the adoption, amendment and repeal of building regulations to the California Code of Regulations, Title 24, also referred to as the California Building Standards Code. This part incorporates by adoption the 2024 International Residential Code of the International Code Council with necessary California amendments.

1.1.2 Purpose. The purpose of this code is to establish the minimum requirements to safeguard the public health, safety and general welfare through structural strength, means of egress facilities, stability, access to persons with disabilities, sanitation, adequate lighting and ventilation and energy conservation; safety to life and property from fire and other hazards attributed to the built environment; and to provide safety to fire fighters and emergency responders during emergency operations.

1.1.3 Scope. The provisions of this code shall apply to the construction, alteration, movement, enlargement, replacement, repair, equip- ment, use and occupancy, location, maintenance, removal and demolition of every detached one- and two-family dwelling and townhouse not more than three stories above grade plane in height with a separate means of egress and structures accessory thereto throughout the State of California.

Exceptions: 1. Live/work units complying with the requirements of Section 508.5 of the California Building Code shall be permitted to be constructed as one- and two-family dwellings or townhouses in accordance with this code, as applicable. Fire suppression required by Section 508.5.7 of the California Building Code when constructed under the California Residential Code for one- and two-family dwellings shall conform to Section 903.3.1.3 of the California Building Code. 2. Owner-occupied lodging houses with five or fewer guestrooms shall be permitted to be constructed in accordance with the California Residential Code for one- and two-family dwellings when equipped with a fire sprinkler system in accordance with Section R309.

1.1.3.1 Classification. Structures or portions of structures shall be classified with respect to occupancy in one or more of the groups _listed in Chapter 3 of the California Building Code.
§ 1.1.1 High relevance — show source text
R109.1.1.1 Concrete slab and under-floor inspection. Concrete slab and under-floor inspections shall be made after in-slab or under-floor reinforcing steel and building service equipment, conduits, piping or other ancillary building trade products or equip- ment are installed, but before any concrete is placed or floor sheathing is installed, including the subfloor.

R109.1.2 Plumbing, mechanical, gas and electrical systems inspection. Rough inspection of plumbing, mechanical, gas and electrical systems shall be made prior to covering or concealment, before fixtures or appliances are set or installed, and prior to framing inspection.

Exception: Backfilling of ground-source heat pump loop systems tested in accordance with the California Mechanical Code prior to inspection shall be permitted.

R109.1.3 Floodplain inspections. For construction in flood hazard areas as established by Table R301.2, upon placement of the lowest floor, including basement, and prior to further vertical construction, the building official shall require submission of documentation, prepared and sealed by a registered design professional, of the elevation of the lowest floor, including basement, required in Section R306.

R109.1.4 Frame and masonry inspection. Inspection of framing and masonry construction shall be made after the roof, masonry, framing, firestopping, draftstopping and bracing are in place and after chimneys and vents to be concealed are completed and the rough electrical, plumbing, heating, wires, pipes and ducts are approved.

R109.1.4.1 Moisture content verification. Moisture content of framing members shall be verified in accordance with the Califor- nia Green Building Standards Code, Chapter 4, Division 4.5.

R109.1.4.2 Lath and gypsum board inspection. Lath and gypsum board inspections shall be made after lathing and gypsum board, interior and exterior, is in place, but before any plastering is applied or gypsum board joints and fasteners are taped and finished.

R109.1.5 Other inspections. In addition to inspections in Sections R109.1.1 through R109.1.4.2, the building official shall have the authority to make or require any other inspections to ascertain compliance with this code and other laws enforced by the building official.

R109.1.5.1 Fire-resistance-rated construction inspection. Where fire-resistance-rated construction is required between dwelling units or due to location on property, the building official shall require an inspection of such construction after lathing or gypsum panel products are in place, but before any plaster is applied, or before panel joints and fasteners are taped and finished. Protection of joints and penetrations in fire-resistance-rated assemblies shall not be concealed from view until inspected and approved.

R109.1.5.2 Special inspections. For special inspections, see California Building Code, Chapter 17.

R109.1.5.3 Weather-exposed balcony and walking surface waterproofing. Where balconies or other elevated walking surfaces are exposed to water from direct or blowing rain, snow or irrigation, and the structural framing is protected by an impervious moisture barrier, all elements of the impervious moisture barrier system shall not be concealed until inspected and approved.

Exception: Where special inspections are provided in accordance with California Building Code Section 1705.1.1, Item 3.

R109.1.6 Final inspection. Final inspection shall be made after the permitted work is complete and prior to occupancy.

Frequently asked questions

When do I count an area as “conditioned floor area” vs “unconditioned”?

Count an area as conditioned if it is served by the building’s heating or cooling system and maintained within conditioned space temperature ranges per the code definitions; otherwise count it as unconditioned. The code’s definitions and rules of construction (see § 100.1) control precise definitions.

If Exception 1 applies, do I still need to meet mandatory commissioning, controls, or lighting measures for non‑dominant spaces?

Yes. Exception 1 allows designing envelope/HVAC/water heating to the dominant occupancy, but mandatory measures in §§ 110.0–130.5, § 150.0 and §§ 160.0–160.9 and the lighting requirements named in the exception still must be met for each occupancy and space.

Can I mix exceptions (use Exception 1 for HVAC and Exception 2 for lighting)?

You can apply whichever exception(s) the building qualifies for. They have different thresholds and covered systems: Exception 1 controls envelope/HVAC/water heating (80% conditioned area), Exception 2 controls indoor lighting (90% combined area). Each exception’s qualifications must be met independently.

If I don’t meet either exception, what must I do?

If neither threshold is met, each occupancy’s spaces must be designed to the Part 6 provisions applicable to that occupancy — i.e., no single-occupancy shortcut is allowed. § 100.0(f).

Are the exceptions mandatory to use if the thresholds are met?

No. They are permissive: you may choose to design systems per the single-occupancy allowance or continue to design each occupancy portion to its own rules. § 100.0(f).

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