CEBC · California Existing Building Code
When is a new certificate of occupancy required for a change?
If your building’s use change places it in a different occupancy classification (for example, office → daycare), the California Existing Building Code requires the authority to issue a new certificate of occupancy only after the building meets the requirements for that new classification (see § 1001.3). Other sections (1001.2, 1004.1, 1011, 1006, 1009) list systems and thresholds that determine what upgrades must be completed before that certificate can be issued.
Last reviewed: July 6, 2026
What the code requires — 2-4 sentences
A new certificate of occupancy is required whenever a change of occupancy results in a different occupancy classification under the California Building Code. The CEBC states plainly: § 1001.3 requires issuance of a certificate of occupancy where a change of occupancy results in a different occupancy classification.
If the new use moves the space into a different occupancy group (for example: from Group B to Group A), the building authority must issue a new certificate of occupancy after the code requirements for that new classification are met.
Requirements in detail
Short plain-English restatement of key defined terms (first use bolded):
- Certificate of occupancy — the official document saying the building/space complies with requirements for the occupancy. See § 1001.2 and § 1001.3.
- Change of occupancy — any change of the use or classification of a building or part of a building; if it changes classification, follow Sections 1002–1011. See § 1001.2.2.
- Partial change of occupancy — a change that affects only a portion of a building; Section § 1001.2.2.1 and § 1011 govern partial changes.
Decision table — when a new CO is required
| Decision factor | Trigger / threshold | Required action | Code reference |
|---|---|---|---|
| Change results in a different occupancy classification | Yes | Issue new certificate of occupancy once requirements for new classification are met | § 1001.3 |
| Change of occupancy (including when Chapter 9 fire-protection thresholds differ) | Change creates different fire-protection threshold or is a change of occupancy | Approval of code official & certificate issued when requirements met | § 1001.2 and § 1004.1 |
| Partial change affecting only a portion of the building | Portion undergoes change of classification (separation may apply) | Apply Section § 1011 for means of egress / fire protection; certificate issued per § 1001.3 if classification changes | § 1001.2.2.1 and § 1011 |
| Project following the CEBC prescriptive method (OSHPD/agency-specific) | Applies to certain state-regulated facilities | See Chapter 5A; certificate requirement reiterated for occupancy changes (506.2) | § 506.2 |
| Structural / systems changes that increase risk category | New occupancy assigns higher Risk Category or increased live loads; exceptions may apply for small areas | The building must comply with applicable structural, seismic, wind, live‑load requirements; certificate only after requirements met | § 1006 series; exceptions for small areas (see next) |
Key thresholds and exceptions that affect whether full upgrades are required
- 10 percent: Where the area of the new occupancy is less than 10 percent of the building area, certain structural or risk-category upgrades are not required (but cumulative changes are considered). See § 1006.2 and related exceptions.
- 20 percent: Plumbing fixture full-upgrade exception — plumbing fixtures must be provided per the California Plumbing Code for a story only where occupant load of that story increases by more than 20 percent. See § 1009.1.
- 50 percent: Several Chapter 9 / work‑area thresholds reference 50 percent (e.g., when work area exceeds 50% of building area), which can trigger additional requirements such as two‑way communications or enhanced systems. See Chapter 5A and Section references in CEBC.
(References above show where those thresholds and exceptions appear in CEBC; they affect what must be done before a certificate can be issued.)
Exceptions & special cases
- A change that does not change the occupancy classification may still require review and specific corrections (mechanical, electrical, plumbing, means of egress, fire protection) but does not automatically require a new CO under § 1001.3—unless other thresholds apply (e.g., Chapter 9 fire-protection thresholds). See § 1001.2 and § 1004.1.
- Small-area exception: If the new occupancy area is less than 10% of the building, some structural/seismic upgrades tied to a higher risk category are not required; still, the authority may require specific corrections and the certificate is issued only when requirements are met. See exceptions in § 1006.
- Agency-specific procedures: For buildings regulated by state agencies (OSHPD, etc.), the prescriptive Chapter 5A contains parallel requirements including certificate issuance (see § 506.2 for the prescriptive method).
- Partial changes: If only part of a building changes classification and is separated, only the separated portion may need to be evaluated/upgraded; still, a certificate is required if the portion’s classification changes. See § 1001.2.2.1 and § 1011.
If a referenced detailed provision is needed (for example, exact uplift requirements for Risk Category reclassification or the list of systems to be upgraded), consult the specific CEBC sections cited above — those sections contain the step‑by‑step criteria for each building system.
Common mistakes
- Assuming a CO is not required when use changes but classification does: the trigger is classification, not just commercial vs. residential use. The controlling rule is § 1001.3.
- Thinking a CO is automatic after permit issuance: the CEBC requires the authority to determine that new‑classification requirements are met before issuing the certificate (see § 1001.2 and § 1001.3).
- Ignoring small-area and occupant‑load exceptions: thresholds like 10% and 20% change whether full upgrades apply; read the exception language in § 1006 and § 1009.1 before assuming full retrofit is required.
- Overlooking Chapter 9 fire-protection thresholds: a change that triggers a higher fire-protection threshold can require systems upgrades even if the occupancy classification stays the same. See § 1004.1 and § 1011.
Worked example — concrete scenario
Scenario: An existing 10,000 ft² one‑story office (Group B) is being converted in full to a daycare (Group E). The owner asks: "Is a new certificate of occupancy required and what upgrades are expected?"
Step 1 — Classification change: Office (Group B) → Daycare (Group E) is a different occupancy classification. That immediately triggers § 1001.3 — a new certificate of occupancy is required after code requirements are met.
Step 2 — Apply Chapter 10 requirements: Because the building changes occupancy classification, Sections 1002 through 1011 (means of egress, fire protection, structural, mechanical, plumbing, etc.) apply. The owner must demonstrate compliance (or accepted alternates) for the new classification before the CO is issued. See § 1001.2.2 and § 1011.
Step 3 — Check thresholds/exceptions:
- If the daycare area were only 800 ft² (8% of building) and the change would otherwise trigger certain structural upgrades because of Risk Category, the 10% exception might limit some structural upgrades — but other systems (fire protection, egress) could still be required. See § 1006 exceptions.
- If occupant load on the story increases by more than 20%, plumbing fixtures will need to be provided per the Plumbing Code. See § 1009.1.
Final: Owner must complete required upgrades/changes (fire protection, means of egress, plumbing, etc., as applicable), have the work accepted by the code official, and then receive the new certificate of occupancy per § 1001.3.
Related provisions
- § 1001.2 — Certificate of occupancy; general rules for changes and fire-protection threshold differences.
- § 1001.2.1 / § 1001.2.2 — Change of use and change of occupancy classification (Sections 1002–1011 apply).
- § 1004.1 — Fire protection triggers when a change of occupancy occurs or fire-protection thresholds differ.
- § 1006 (1006.1–1006.4) — Structural (live loads, snow/wind, seismic) requirements and exceptions for occupancy changes.
- § 1009.1 — Plumbing fixture requirements; 20 percent occupant-load threshold exception.
- § 1011 — Detailed provisions for change of occupancy classification (means of egress, fire protection, etc.).
- § 506.2 — Certificate of occupancy requirement in Chapter 5A (prescriptive method / OSHPD applications).
Code references
Grounded in the retrieved California Existing Building Code — click a citation to read the verbatim passage:
CEBC § 1.1 High relevance — show source text
Exception: The building need not be made to comply with Chapter 16 A of the California Building Code unless required by Section 506 A .5.
506 A .1.1 Change in function . A change in function shall require compliance with all the functional requirements for new construc- tion in the California Building Code, including requirements in California Building Code Section 1224. Compliance shall be only as necessary to meet the specific provisions and is not intended to require the entire building be brought into compliance.
Exception: Minimum room clearances, areas and dimensions may meet the requirements of the 2001 California Building Code for existing rooms re-used for a similar purpose, subject to the approval of OSHPD.
506 A .2 Certificate of occupancy. A certificate of occupancy shall be issued where it has been determined that the requirements for the new occupancy classification have been met.
506 A .3 Stairways. An existing stairway shall not be required to comply with the requirements of Section 1011 of the California Build- ing Code where the existing space and construction does not allow a reduction in pitch or slope.
506 A .4 Existing emergency escape and rescue openings. Where a change of occupancy would require an emergency escape and rescue opening in accordance with Section 1031.1 of the California Building Code, operable windows serving as the emergency escape and rescue opening shall comply with the following:
- An existing operable window shall provide a minimum net clear opening of 4 square feet (0.38 m [2] ) with a minimum net clear opening height of 22 inches (559 mm) and a minimum net clear opening width of 20 inches (508 mm).
- A replacement window where such window complies with both of the following: 2.1. The replacement window meets the size requirements in Item 1. 2.2. The replacement window is the manufacturer’s largest standard size window that will fit within the existing frame or existing rough opening. The replacement window shall be permitted to be of the same operating style as the existing window or a style that provides for an equal or greater window opening area than the existing window.
506 A .5 Structural. Any building undergoing a change of occupancy shall satisfy the requirements of this section.
506 A .5.1 Live loads. Structural elements carrying tributary live loads from an area with a change of occupancy shall satisfy the requirements of Section 1607 A of the California Building Code . Design live loads for areas of new occupancy shall be based on Section 1607 A of the California Building Code . Design live loads for other areas shall be permitted to use previously approved design live loads.
Exception: Structural elements whose demand-capacity ratio considering the change of occupancy is not more than 5 percent greater than the demand-capacity ratio based on previously approved live loads need not comply with this section.
506 A .5.2 Snow and wind loads. Where a change of occupancy results in a structure being assigned to a higher risk category, the structure shall satisfy the requirements of Sections 1608 A and 1609 A of the California Building Code for the new risk category.
Exception: Where the area of the new occupancy is less than 10 percent of the building area, compliance with this section is not required. The cumulative effect of occupancy changes over time shall be considered.
CEBC § 422.3 High relevance — show source text
503 A .16 Reserved.
503 A .17 Ambulatory care facilities. Where a work area exceeds 50 percent of the building area and the work area includes an existing ambulatory care facility, the following shall be provided:
- A smoke compartment in accordance with Section 422.3 of the California Building Code where the alteration results in an ambulatory care facility greater than 10,000 square feet on one story.
- Separation from adjacent spaces in accordance with Section 422.2 of the California Building Code, where any such facility has the potential for four or more care recipients are to be incapable of self-preservation at any time.
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PRESCRIPTIVE COMPLIANCE METHOD
503 A .18 Reserved.
503 A .19 Reserved.
503 A .20 Two-way communications systems. Where the work area for alterations exceeds 50 percent of the building area and the building has elevator service, a two-way communication systems shall be provided where required by Section 1009.8 of the Califor- nia Building Code.
SECTION 504 A
RESERVED
SECTION 505 A
RESERVED
SECTION 506 A —CHANGE OF OCCUPANCY
506 A .1 Compliance. A change of occupancy shall not be made in any building unless that building is made to comply with the requirements of the California Building Code for the use or occupancy. Changes of occupancy in a building or portion thereof shall be such that the existing building is not less complying with the provisions of this code than the existing building or structure was prior to the change. Subject to the approval of the building official, changes of occupancy shall be permitted without complying with all of the requirements of this code for the new occupancy, provided that the new occupancy is less hazardous, based on life and fire risk, than the existing occupancy.
Exception: The building need not be made to comply with Chapter 16 A of the California Building Code unless required by Section 506 A .5.
506 A .1.1 Change in function . A change in function shall require compliance with all the functional requirements for new construc- tion in the California Building Code, including requirements in California Building Code Section 1224. Compliance shall be only as necessary to meet the specific provisions and is not intended to require the entire building be brought into compliance.
Exception: Minimum room clearances, areas and dimensions may meet the requirements of the 2001 California Building Code for existing rooms re-used for a similar purpose, subject to the approval of OSHPD.
506 A .2 Certificate of occupancy. A certificate of occupancy shall be issued where it has been determined that the requirements for the new occupancy classification have been met.
506 A .3 Stairways. An existing stairway shall not be required to comply with the requirements of Section 1011 of the California Build- ing Code where the existing space and construction does not allow a reduction in pitch or slope.
CEBC § 1001.1 High relevance — show source text
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10 CHANGE OF OCCUPANCY
User notes:
About this chapter : The purpose of this chapter is to provide regulations for the circumstances where an existing building is subject to a change of occupancy or a change of occupancy classification. A change of occupancy is not to be confused with a change of occupancy classification. The California Building Code defines different occupancy classifications in Chapter 3 and special occupancy requirements in Chapter 4. Within specific occupancy classifications there can be many different types of actual activities that can take place. For instance, a Group A-3 occupancy classification deals with a wide variation of different types of activities, including bowling alleys and courtrooms, indoor tennis courts and dance halls. When a facility changes use from, for example, a bowling alley to a dance hall, the occupancy classification remains A-3, but the different uses could lead to drastically different code requirements. Therefore, this chapter deals with the special circumstances that are associated with a change in the use of a building within the same occupancy classification as well as a change of occupancy classification.
SECTION 1001—GENERAL
1001.1 Scope. The provisions of this chapter shalle a change of occupancy occurs, as defined in Section 202.
1001.2 Certificate of occupancy. A change of occupancy or a change of occupancy within a space where there is a different fire protection system threshold requirement in Chapter 9 of th apply where current California Building Code than exists in the current building or space shall not be made to any structure without the approval of the code official. A certificate of occupancy shall be issued where it has been determined that the requirements for the change of occupancy have been met.
1001.2.1 Change of use. Any work undertaken in connection with a change in use shall conform to the applicable requirements for the work as classified in Chapter 6 and to the requirements of Sections 1002 through 1010.
1001.2.2 Change of occupancy classification. Where a building undergoes a change of occupancy classification, the provisions of Sections 1002 through 1011 shall apply.
1001.2.2.1 Partial change of occupancy. Where a portion of an existing building undergoes a change of occupancy classification, Section 1011 shall apply.
1001.3 Certificate of occupancy required. A certificate of occupancy shall be issued where a change of occupancy occurs that results in a different occupancy classification as determined by the California Building Code .
SECTION 1002—SPECIAL USE AND OCCUPANCY
1002.1 Compliance with the building code. Where an existing building or part of an existing building undergoes a change of occupancy to one of the special use or occupancy categories as described in Chapter 4 in the California Building Code, the building shall comply with all of the requirements of Chapter 4 of the California Building Code applicable to the special use or occupancy.
1002.2 Incidental uses. Where a portion of a building undergoes a change of occupancy to one of the incidental uses listed in Table 509.1 of the California Building Code, the incidental use shall comply with Section 509 of the California Building Code applicable to the incidental use.
SECTION 1003—BUILDING ELEMENTS AND MATERIALS
1003.1 General. Building elements and materials in portions of buildings undergoing a change of occupancy classification shall comply with Section 1011.
SECTION 1004—FIRE PROTECTION
CEBC § 1006.3 High relevance — show source text
Exception: Where the area of the new occupancy is less than 10 percent of the building area. The cumulative effect of occupancy changes over time shall be considered.
[BS] 1006.3 Seismic loads. Where a change of occupancy results in a building being assigned to a higher risk category, or where the change is from a Group S or Group U occupancy to any occupancy other than Group S or Group U, the lateral force-resisting system of the building shall comply with Section 304.3.1 for the new risk category. Where a change of occupancy results in a building being assigned to Risk Category IV and Seismic Design Category D or F, nonstructural components serving any portion of the building changed to Risk Category IV shall comply with the requirements of Section 1613 of the California Building Code or shall comply with ASCE 41 using an objective of operational nonstructural performance with the BSE-1N earthquake hazard level.
Exceptions:
Where a change of use results in a building being reclassified from Risk Category I or II to Risk Category III and the seismic coefficient, S DS, is less than 0.33, compliance with this section is not required.
Where the area of the new occupancy is less than 10 percent of the building area, the occupancy is not changing from a Group S or Group U occupancy, and the new occupancy is not assigned to Risk Category IV, compliance with this section is not required. The cumulative effect of occupancy changes over time shall be considered.
Reserved.
Where the change is from a Group S or Group U occupancy and there is no change of risk category, compliance with Section 304.3.2 shall be permitted.
[BS] 1006.4 Access to Risk Category IV. Any structure that provides operational access to an adjacent structure assigned to Risk Category IV as the result of a change of occupancy shall itself comply with Sections 1608 and 1609 of the California Building Code and Section 304.3.1 of this code. Where operational access to Risk Category IV is less than 10 feet (3048 mm) from either an interior lot line or from another structure, access protection from potential falling debris shall be provided.
SECTION 1007—ELECTRICAL
1007.1 Special occupancies. Where the occupancy of an existing building or part of an existing building is changed to one of the following special occupancies as described in the California Electrical Code, the electrical wiring and equipment of the building or portion thereof that contains the proposed occupancy shall comply with the applicable requirements of the California Electrical Code :
Hazardous locations.
Commercial garages, repair and storage.
Aircraft hangars.
Gasoline dispensing and service stations.
Bulk storage plants.
Spray application, dipping and coating processes.
Reserved.
Places of assembly.
Theaters, audience areas of motion picture and television studios, and similar locations.
Motion picture and television studios and similar locations.
Motion picture projectors.
Agricultural buildings.
1007.2 Unsafe conditions. Where the occupancy of an existing building or part of an existing building is changed, all unsafe conditions shall be corrected without requiring that all parts of the electrical system comply with the California Electrical Code .
1007.3 Service upgrade. Where the occupancy of an existing building or part of an existing building is changed, electrical service shall be upgraded to meet the requirements of the California Electrical Code for the new occupancy.
CEBC § 0.33 High relevance — show source text
Exceptions:
- Where the area of the new occupancy is less than 10 percent of the building area, the occupancy is not changing from a Group S or Group U occupancy, and the new occupancy is not assigned to Risk Category IV, compliance with this section is not required. The cumulative effect of occupancy changes over time shall be considered.
- Where a change of use results in a building being reclassified from Risk Category I or II to Risk Category III and the seismic coefficient, S DS, is less than 0.33, compliance with this section is not required.
- Unreinforced masonry bearing wall buildings assigned to Risk Category III and to Seismic Design Category A or B, shall be permitted to use Appendix Chapter A1 of this code.
- Where the change is from a Group S or Group U occupancy and there is no change of risk category, compliance with Section 304.3.2 shall be permitted.
[BS] 506.5.4 Access to Risk Category IV. Any structure that provides operational access to an adjacent structure assigned to Risk Category IV as the result of a change of occupancy shall itself comply with Sections 1608 and 1609 of the California Building Code and Section 304.3.1 of this code. Where operational access to the Risk Category IV structure is less than 10 feet (3048 mm) from either an interior lot line or from another structure, access protection from potential falling debris shall be provided.
506.6 Enhanced classroom acoustics. In Group E occupancies, where the work area exceeds 50 percent of the building area, enhanced classroom acoustics shall be provided in all classrooms with a volume of 20,000 cubic feet (565 m [3] ) or less. Enhanced classroom acoustics shall comply with the reverberation time in Section 808 of ICC A117.1.
SECTION 507—HISTORIC BUILDINGS
507.1 Historic buildings. The provisions of the California Historical Building Code (Part 8, Title 24, C.C.R), shall apply to qualified historical buildings or properties.
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CALIFORNIA EXISTING BUILDING CODE – MATRIX ADOPTION TABLE
CHAPTER 5A – PRESCRIPTIVE COMPLIANCE METHOD [OSHPD 1]
(Matrix Adoption Tables are nonregulatory, intended only as an aid to the code user. See Chapter 1 for state agency authority and building applications.)
CEBC § 1004.1 High relevance — show source text
SECTION 1004—FIRE PROTECTION
1004.1 General. Fire protection requirements in Section 1011 shall apply where either of the following occur:
- A building or portion thereof undergoes a change of occupancy.
- A building or portion thereof undergoes a change of occupancy and there is a different fire protection system threshold requirement in Chapter 9 of the current California Building Code than exists in the current building or portion thereof.
SECTION 1005—MEANS OF EGRESS
1005.1 General. Means of egress in portions of buildings undergoing a change of occupancy classification shall comply with Section 1011.
SECTION 1006—STRUCTURAL
[BS] 1006.1 Live loads. Structural elements carrying tributary live loads from an area with a change of occupancy shall satisfy the requirements of Section 1607 of the California Building Code . Design live loads for areas of new occupancy shall be based on Section 1607 of the California Building Code . Design live loads for other areas shall be permitted to use previously approved design live loads.
Exception: Structural elements whose demand-capacity ratio considering the change of occupancy is not more than 5 percent greater than the demand-capacity ratio based on previously approved live loads.
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CHANGE OF OCCUPANCY
[BS] 1006.2 Snow and wind loads. Where a change of occupancy results in a structure being assigned to a higher risk category, the structure shall satisfy the requirements of Sections 1608 and 1609 of the California Building Code for the new risk category.
Exception: Where the area of the new occupancy is less than 10 percent of the building area. The cumulative effect of occupancy changes over time shall be considered.
[BS] 1006.3 Seismic loads. Where a change of occupancy results in a building being assigned to a higher risk category, or where the change is from a Group S or Group U occupancy to any occupancy other than Group S or Group U, the lateral force-resisting system of the building shall comply with Section 304.3.1 for the new risk category. Where a change of occupancy results in a building being assigned to Risk Category IV and Seismic Design Category D or F, nonstructural components serving any portion of the building changed to Risk Category IV shall comply with the requirements of Section 1613 of the California Building Code or shall comply with ASCE 41 using an objective of operational nonstructural performance with the BSE-1N earthquake hazard level.
Exceptions:
Where a change of use results in a building being reclassified from Risk Category I or II to Risk Category III and the seismic coefficient, S DS, is less than 0.33, compliance with this section is not required.
Where the area of the new occupancy is less than 10 percent of the building area, the occupancy is not changing from a Group S or Group U occupancy, and the new occupancy is not assigned to Risk Category IV, compliance with this section is not required. The cumulative effect of occupancy changes over time shall be considered.
Reserved.
Where the change is from a Group S or Group U occupancy and there is no change of risk category, compliance with Section 304.3.2 shall be permitted.
CEBC § 2.1. High relevance — show source text
- A replacement window where such window complies with both of the following: 2.1. The replacement window meets the size requirements in Item 1. 2.2. The replacement window is the manufacturer’s largest standard size window that will fit within the existing frame or existing rough opening. The replacement window shall be permitted to be of the same operating style as the existing window or a style that provides for an equal or greater window opening area than the existing window.
506 A .5 Structural. Any building undergoing a change of occupancy shall satisfy the requirements of this section.
506 A .5.1 Live loads. Structural elements carrying tributary live loads from an area with a change of occupancy shall satisfy the requirements of Section 1607 A of the California Building Code . Design live loads for areas of new occupancy shall be based on Section 1607 A of the California Building Code . Design live loads for other areas shall be permitted to use previously approved design live loads.
Exception: Structural elements whose demand-capacity ratio considering the change of occupancy is not more than 5 percent greater than the demand-capacity ratio based on previously approved live loads need not comply with this section.
506 A .5.2 Snow and wind loads. Where a change of occupancy results in a structure being assigned to a higher risk category, the structure shall satisfy the requirements of Sections 1608 A and 1609 A of the California Building Code for the new risk category.
Exception: Where the area of the new occupancy is less than 10 percent of the building area, compliance with this section is not required. The cumulative effect of occupancy changes over time shall be considered.
506 A .5.3 Seismic loads (seismic force-resisting system). Where a change of occupancy results in a building being assigned to a higher risk category, the lateral force-resisting system of the building shall comply with the California Building Code Section 1613A or Section 304A.3.4 of this code for the new risk category. Where a change of occupancy results in a building being assigned to Risk Category IV and Seismic Design Category D or F, nonstructural components serving any portion of the building changed to Risk Category IV shall comply with the requirements of Section 1613 A of the California Building Code or shall comply with ASCE 41 -23 using an objective of Operational nonstructural performance with the BSE-1N earthquake hazard level.
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CALIFORNIA EXISTING BUILDING CODE – MATRIX ADOPTION TABLE
CHAPTER 6 – CLASSIFICATION OF WORK
(Matrix Adoption Tables are nonregulatory, intended only as an aid to the code user. See Chapter 1 for state agency authority and building applications.)
CEBC § 1008.1 High relevance — show source text
SECTION 1008—MECHANICAL
1008.1 Mechanical requirements. Where the occupancy of an existing building or part of an existing building is changed such that the new occupancy is subject to different kitchen exhaust requirements or to increased mechanical ventilation requirements in accordance with the California Mechanical Code, the new occupancy shall comply with the respective California Mechanical Code provisions.
SECTION 1009—PLUMBING
1009.1 Increased demand. Where the occupancy of an existing building or part of an existing building is changed such that the new occupancy is subject to increased or different plumbing fixture requirements or to increased water supply requirements in accor
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dance with the California Plumbing Code, the new occupancy shall comply with the intent of the respective California Plumbing Code provisions.
Exception: Only where the occupant load of the story is increased by more than 20 percent, plumbing fixtures for the story shall be provided in quantities specified in the California Plumbing Code based on the increased occupant load.
1009.2 Food-handling occupancies. If the new occupancy is a food-handling establishment, all existing sanitary waste lines above the food or drink preparation or storage areas shall be panned or otherwise protected to prevent leaking pipes or condensation on pipes from contaminating food or drink. New drainage lines shall not be installed above such areas and shall be protected in accordance with the California Plumbing Code .
1009.3 Interceptor required. If the new occupancy will produce grease or oil-laden wastes, interceptors shall be provided as required in the California Plumbing Code .
1009.4 Chemical wastes. If the new occupancy will produce chemical wastes, the following shall apply:
- If the existing piping is not compatible with the chemical waste, the waste shall be neutralized prior to entering the drainage system or the piping shall be changed to a compatible material.
- Chemical waste shall not discharge to a public sewer system without the approval of the sewage authority.
SECTION 1010—OTHER REQUIREMENTS
1010.1 Light and ventilation. Light and ventilation shall comply with the requirements of the California Building Code for the new
occupancy.
SECTION 1011—CHANGE OF OCCUPANCY CLASSIFICATION
1011.1 General. The provisions of this section shall apply to buildings or portions thereof undergoing a change of occupancy classification. This includes a change of occupancy classification within a group as well as a change of occupancy classification from one group to a different group. The provisions of this section shall also apply where there is a change of occupancy within a building or portion thereof and there is a different fire protection system threshold requirement in Chapter 9 of the current California Building Code than exists in the current building or space. Such buildings shall also comply with Sections 1002 through 1010 of this code.
1011.2 Fire protection systems. Fire protection systems shall be provided in accordance with Sections 1011.2.1 and 1011.2.2.
CEBC § 1001.2.1 High relevance — show source text
1001.2.1 Change of use. Any work undertaken in connection with a change in use shall conform to the applicable requirements for the work as classified in Chapter 6 and to the requirements of Sections 1002 through 1010.
1001.2.2 Change of occupancy classification. Where a building undergoes a change of occupancy classification, the provisions of Sections 1002 through 1011 shall apply.
1001.2.2.1 Partial change of occupancy. Where a portion of an existing building undergoes a change of occupancy classification, Section 1011 shall apply.
1001.3 Certificate of occupancy required. A certificate of occupancy shall be issued where a change of occupancy occurs that results in a different occupancy classification as determined by the California Building Code .
SECTION 1002—SPECIAL USE AND OCCUPANCY
1002.1 Compliance with the building code. Where an existing building or part of an existing building undergoes a change of occupancy to one of the special use or occupancy categories as described in Chapter 4 in the California Building Code, the building shall comply with all of the requirements of Chapter 4 of the California Building Code applicable to the special use or occupancy.
1002.2 Incidental uses. Where a portion of a building undergoes a change of occupancy to one of the incidental uses listed in Table 509.1 of the California Building Code, the incidental use shall comply with Section 509 of the California Building Code applicable to the incidental use.
SECTION 1003—BUILDING ELEMENTS AND MATERIALS
1003.1 General. Building elements and materials in portions of buildings undergoing a change of occupancy classification shall comply with Section 1011.
SECTION 1004—FIRE PROTECTION
1004.1 General. Fire protection requirements in Section 1011 shall apply where either of the following occur:
- A building or portion thereof undergoes a change of occupancy.
- A building or portion thereof undergoes a change of occupancy and there is a different fire protection system threshold requirement in Chapter 9 of the current California Building Code than exists in the current building or portion thereof.
SECTION 1005—MEANS OF EGRESS
1005.1 General. Means of egress in portions of buildings undergoing a change of occupancy classification shall comply with Section 1011.
SECTION 1006—STRUCTURAL
[BS] 1006.1 Live loads. Structural elements carrying tributary live loads from an area with a change of occupancy shall satisfy the requirements of Section 1607 of the California Building Code . Design live loads for areas of new occupancy shall be based on Section 1607 of the California Building Code . Design live loads for other areas shall be permitted to use previously approved design live loads.
Exception: Structural elements whose demand-capacity ratio considering the change of occupancy is not more than 5 percent greater than the demand-capacity ratio based on previously approved live loads.
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[BS] 1006.2 Snow and wind loads. Where a change of occupancy results in a structure being assigned to a higher risk category, the structure shall satisfy the requirements of Sections 1608 and 1609 of the California Building Code for the new risk category.
CEBC § 506.1 High relevance — show source text
SECTION 506—CHANGE OF OCCUPANCY
506.1 Compliance. A change of occupancy shall not be made in any building unless that building is made to comply with the requirements of the California Building Code for the use or occupancy. Changes of occupancy in a building or portion thereof shall be such that the existing building is not less complying with the provisions of this code than the existing building or structure was prior to the change. Subject to the approval of the code official, changes of occupancy shall be permitted without complying with all of the requirements of this code for the new occupancy, provided that the new occupancy is less hazardous, based on life and fire risk, than the existing occupancy.
Exception: The building need not be made to comply with Chapter 16 of the California Building Code unless required by Section 506.5.
506.1.1 Change in the character of use. A change of occupancy with no change of occupancy classification shall not be made to any structure that will subject the structure to any special provisions of the applicable California Codes, without approval of the code official. Compliance shall be only as necessary to meet the specific provisions and is not intended to require the entire building be brought into compliance.
506.1.2 Change in function. [OSHPD 1R, 2, 4 and 5] A change in function shall require compliance with all the functional require- ments for new construction in the California Building Code, including requirements in Sections 1224, 1225, 1226, 1227 and 1228.
Exception [OSHPD 1R] : Hospital buildings removed from acute care service adapted for re-use as skilled nursing facilities, acute psychiatric hospitals or out-patient services of a hospital may be permitted to meet the minimum room clearances, areas and dimensions of the 2001 California Building Code for existing rooms re-used for a similar purpose, subject to the approval of OSHPD.
506.2 Certificate of occupancy. A certificate of occupancy shall be issued where it has been determined that the requirements for the new occupancy classification have been met.
506.3 Stairways. An existing stairway shall not be required to comply with the requirements of Section 1011 of the California Build- ing Code where the existing space and construction does not allow a reduction in pitch or slope.
506.4 Existing emergency escape and rescue openings. Where a change of occupancy would require an emergency escape and rescue opening in accordance with Section 1031.1 of the California Building Code, operable windows serving as the emergency escape and rescue opening shall comply with the following:
- An existing operable window shall provide a minimum net clear opening of 4 square feet (0.38 m [2] ) with a minimum net clear opening height of 22 inches (559 mm) and a minimum net clear opening width of 20 inches (508 mm).
- A replacement window where such window complies with both of the following: 2.1. The replacement window meets the size requirements in Item 1. 2.2. The replacement window is the manufacturer’s largest standard size window that will fit within the existing frame or existing rough opening. The replacement window shall be permitted to be of the same operating style as the existing window or a style that provides for an equal or greater window opening area than the existing window.
[BS] 506.5 Structural. Any building undergoing a change of occupancy shall satisfy the requirements of this section.
CEBC § 1007.1 High relevance — show source text
3 Exception 3|X|||||||||||||||||||||||| |1007||||†|†|||||||||||||||||||| |1007.1|||X|||||||||||||||||||||| |1009.2 – 1009.4||||†|†|||||||||||||||||||| |1011.2.1|||X|||||||||||||||||||||| |1011.2.2|||X|||||||||||||||||||||| |1011.4||||†|†|||||||||||||||||||| |1011.5.1|||X|||||||||||||||||||||| |1011.5.1 Exception 8||||†|†|||||||||||||||||||| |Table 1011.5|||X|||||||||||||||||||||| |1011.5.2|||X|||||||||||||||||||||| |1011.5.2 Exception 2||||†|†|||||||||||||||||||| |1011.5.4|||X|||||||||||||||||||||| |1011.5.5|||X|||||||||||||||||||||| |1011.6.1 Exception 1||||†|†|||||||||||||||||||| |1011.7.1 Exception||||†|†|||||||||||||||||||| |1011.8.2|||X||||||||||||||||||||||
The state agency does not adopt sections identified with the following symbol: The Office of the State Fire Marshal’s adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.
2025 CALIFORNIA EXISTING BUILDING CODE 10-1
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
10-2 2025 CALIFORNIA EXISTING BUILDING CODE
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
10 CHANGE OF OCCUPANCY
User notes:
About this chapter : The purpose of this chapter is to provide regulations for the circumstances where an existing building is subject to a change of occupancy or a change of occupancy classification. A change of occupancy is not to be confused with a change of occupancy classification. The California Building Code defines different occupancy classifications in Chapter 3 and special occupancy requirements in Chapter 4. Within specific occupancy classifications there can be many different types of actual activities that can take place. For instance, a Group A-3 occupancy classification deals with a wide variation of different types of activities, including bowling alleys and courtrooms, indoor tennis courts and dance halls. When a facility changes use from, for example, a bowling alley to a dance hall, the occupancy classification remains A-3, but the different uses could lead to drastically different code requirements. Therefore, this chapter deals with the special circumstances that are associated with a change in the use of a building within the same occupancy classification as well as a change of occupancy classification.
SECTION 1001—GENERAL
1001.1 Scope. The provisions of this chapter shalle a change of occupancy occurs, as defined in Section 202.
1001.2 Certificate of occupancy. A change of occupancy or a change of occupancy within a space where there is a different fire protection system threshold requirement in Chapter 9 of th apply where current California Building Code than exists in the current building or space shall not be made to any structure without the approval of the code official. A certificate of occupancy shall be issued where it has been determined that the requirements for the change of occupancy have been met.
Frequently asked questions
Does every change of use need a certificate of occupancy?
Not necessarily — the CEBC requires a new certificate only when the change results in a different occupancy classification as determined by the California Building Code (see § 1001.3) or when other thresholds (e.g., Chapter 9 fire-protection differences) apply (see § 1001.2).
If I convert only part of a building, is a CO required?
If the portion’s occupancy classification changes, a certificate is required for that changed portion; Section § 1001.2.2.1 and § 1011 explain partial-change rules and separations.
What if the new use increases occupant load by less than 20%?
Plumbing fixture counts tied to occupant load are triggered only when occupant load increases by more than 20% for the story; below that threshold the full plumbing‑fixture upgrade in § 1009.1 is not mandated (but other items could still be required).
Are there small-area exceptions to upgrades required before issuing a CO?
Yes. Several structural and seismic upgrade requirements have an exception when the new occupancy area is less than 10 percent of the building area — but the code requires the cumulative effect of changes over time be considered. See § 1006 exceptions.
Where do I find the step-by-step list of items that must be met before the CO is issued?
Start with § 1001.2–§ 1011 (Chapter 10) for which systems to check (fire protection, egress, structural, mechanical, plumbing, etc.). For the prescriptive method in state‑regulated facilities, see § 506.2 (Chapter 5A).
More in California Existing Building Code
- Administration and Definitions (Scope, enforcement, code official duties, definitions)
- Provisions for All Compliance Methods (general requirements that apply to all compliance options; Chapter 3 / 3A)
- Seismic retrofit and evaluation (Appendix A and seismic provisions/sections for evaluation and retrofit)
- Referenced Standards and Appendices (Chapter 16 and Appendices A–E, Resource A)
- Repairs (Chapter 4 — repair-specific rules for materials, means of egress, structural, MEP, etc.)
- Alterations — Level 1, Level 2, Level 3 (technical requirements for each alteration level; Chapters 7–9)
- Change of Occupancy and Additions (requirements for occupancy changes and additions; Chapters 10–11)
- Compliance Methods — Prescriptive, Work Area, Performance (Chapters 5, 6–11, 13)
- Relocated Buildings (requirements for buildings moved or relocated; Chapter 14)
- Construction Safeguards (site safety, means of egress and life-safety during construction; Chapter 15)
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