CWUIC · California Wildland-Urban Interface Code
Standby power, fuel‑clearance and reliability for stationary water supply facilities
If your water tank or pump in a WUI area relies on electricity, the CWUIC requires standby power able to run for at least two hours and defensible fuel clearance around tanks and pump houses (see §§ 404.10, 404.10.3); exceptions apply for underground service and single‑family service — confirm design details with the code official and follow the CBC/CFC provisions referenced by the CWUIC.
Last reviewed: July 6, 2026
What the code requires — 2-4 sentences
The California Wildland‑Urban Interface Code requires increased water supply reliability for stationary water supply facilities in WUI areas under § 404.10 and mandates standby power for electrically dependent pumps, controllers and related equipment under § 404.10.3. The standby power source must be capable of providing power for not less than 2 hours; the code also requires defensible space / fuel clearance around tanks and pump buildings in accordance with § 404.10.2 (which references Section 603 for defensible‑space requirements).
Provide an automatic, 2‑hour standby power source and keep a clear, defensible zone around water tanks, pump houses and electrical equipment so the required water supply remains available during wildfire events.
Requirements in detail
Scope and objective
- The reliability provisions appear in § 404.10; the objective in § 404.10.1 is to reduce exposure of vegetative fuels to electrically powered systems so water supplies remain available during wildfires.
- The requirements apply to stationary water supply facilities within designated wildland‑urban interface areas that are dependent on electrical power. The code text for the standby requirement is in § 404.10.3.
Standby power (what the code says)
- What must be provided: Standby power to pumps, controllers and related electrical equipment so electrically dependent stationary water supply facilities can provide the required water supply. § 404.10.3.
- Standards compliance: The standby power system must be in accordance with Section 2702 of the California Building Code and Section 1203 of the California Fire Code (these referenced sections contain detailed requirements for standby/emergency systems). § 404.10.3.
- Minimum duration: The standby power source shall be capable of providing power for not less than 2 hours. § 404.10.3.
Fuel clearance / defensible space (what the code says)
- Defensible space around water facilities: Defensible space shall be provided around water tank structures, water supply pumps and pump houses in accordance with Section 603. This is stated in § 404.10.2.
- Appendix guidance (A107): Appendix A provides more prescriptive guidance: a fuel modification area of not less than 30 feet clear of non‑fire‑resistive vegetation around water storage and pumping facilities, and removal of tree portions that extend within 30 feet of combustible portions of the facilities. Appendix A also reiterates the standby power requirement and the same 2‑hour minimum duration. Appendix A text is part of the CWUIC.
Exceptions & interaction with other codes
- Exception 1 in § 404.10.3: Where approved by the code official, a standby power supply is not required if the primary power service to the stationary water supply facility is underground. § 404.10.3.
- Exception 2 in § 404.10.3: A standby power supply is not required where the stationary water supply facility serves not more than one single‑family dwelling. § 404.10.3.
- The CWUIC references CBC §2702 and CFC §1203 for design/installation/operation details of standby systems; follow those referenced sections for automatic transfer, listing, fuel requirements, and other technical details. § 404.10.3.
Decision‑relevant summary table
| Decision factor | Required value / action | Code Reference |
|---|---|---|
| Standby power provided to pumps/controllers/related equipment | Yes — for electrically dependent stationary water supply facilities | § 404.10.3 |
| Minimum standby power duration | Not less than 2 hours | § 404.10.3 |
| Standard(s) to follow for standby system design/installation | CBC Section 2702 and CFC Section 1203 (referenced) | § 404.10.3 |
| Fuel clearance / defensible space around tanks/pumps | Provide defensible space per Section 603; Appendix A recommends 30 feet fuel modification area around water storage and pumping facilities | § 404.10.2 and Appendix A (A107) |
| Exception — underground primary service | Standby supply not required if primary power service is underground and approved by code official | § 404.10.3 Exception 1 |
| Exception — serves single dwelling | Standby not required if facility serves ≤ one single‑family dwelling | § 404.10.3 Exception 2 |
Exceptions & special cases
- Underground primary service: The code permits the code official to waive standby power where the primary power service to the water facility is underground; obtain approval in writing from the code official. § 404.10.3 Exception 1.
- Single‑family service: If the facility serves not more than one single‑family dwelling, standby power is not required. § 404.10.3 Exception 2.
- Alternative compliance & referenced codes: The CWUIC defers technical design details (automatic transfer time, listing, fuel capacity, installation) to CBC §2702 and CFC §1203; where the CWUIC is silent on sizing/transfer/automatic operation, use those referenced sections and consult the code official. § 404.10.3.
- Appendix A (A107): Non‑mandatory Appendix A provides a 30‑foot fuel modification recommendation and reiterates the 2‑hour standby requirement; check whether your jurisdiction enforces Appendix A provisions or uses them as guidance. Appendix A A107.3–A107.5.
Common mistakes
- Assuming any backup source qualifies — the CWUIC requires a standby power system in accordance with CBC §2702 and CFC §1203; an improvised, non‑code generator hookup may not meet those referenced standards. § 404.10.3.
- Forgetting automatic transfer — CBC/CFC standards referenced by the CWUIC address automatic transfer/load‑transfer timing; failing to provide automatic transfer can leave pumps inoperative during outages. § 404.10.3.
- Neglecting fuel‑clearance around auxiliary equipment — the code requires defensible space around water tank structures, pumps and pump houses (see § 404.10.2 and Section 603), and Appendix A gives specific 30‑ft guidance. Clearing only the immediate structure but not the pump house and electrical enclosures is a common oversight.
- Misapplying exceptions — the underground service exception requires approval by the code official; do not assume underground service is automatically acceptable without approval. § 404.10.3 Exception 1.
Worked example — concrete scenario
Scenario: A small community water tank and pump house serve a neighborhood (10 residences). The pump motor is rated at 5 hp (≈ 3.7 kW). Controls and ancillary equipment draw an additional 0.5 kW. The system is electrically dependent and located in a designated WUI area.
Step 1 — Code requirements:
- Provide standby power for pumps/controllers/related equipment per § 404.10.3 and ensure the standby source can power the load for not less than 2 hours.
Step 2 — Energy needed (example calculation):
- Continuous power required ≈ 3.7 kW + 0.5 kW = 4.2 kW.
- Energy to cover 2 hours = 4.2 kW × 2 h = 8.4 kWh.
Step 3 — Sizing an example generator/battery solution (illustrative only; consult CBC/CFC):
- A 5 kW standby generator (rated continuous) would cover the 4.2 kW load with margin.
- Fuel capacity or fuel supply must allow the generator to run ≥ 2 hours without refueling (the CWUIC minimum). § 404.10.3. For battery systems, ensure the inverter and battery bank supply ≥ 8.4 kWh usable energy plus reserve and derating for efficiency/temperature.
- Confirm installation, transfer switches, listings and automatic operation per CBC § 2702 / CFC § 1203 before final selection.
Step 4 — Fuel clearance:
- Provide defensible space around the tank and pump house in accordance with § 404.10.2 and Section 603; Appendix A recommends 30 feet clear of nonfire‑resistive vegetation around water storage and pumping facilities.
Note: The example generator sizing above is illustrative — the CWUIC sets the 2‑hour duration requirement but defers detailed design and equipment listing/installation to CBC and CFC referenced sections. Confirm final numbers and listing/installation with the code official.
Related provisions
- § 404.10.1 — Objective (reliability objective; exposure reduction).
- § 404.10.2 — Clearance of fuel (defensible space for water tanks, pumps and pump houses; references Section 603).
- § 404.9 — Testing and maintenance of water sources and equipment (keep in operative condition).
- Appendix A, A107 — Protection of pumps and water storage facilities (30‑ft fuel modification guidance; reiterates 2‑hour standby requirement).
- CBC Section 2702 — Referenced for standby/emergency power system design and operation (referenced by § 404.10.3).
- CFC Section 1203 — Referenced for emergency and standby power systems (referenced by § 404.10.3).
Code references
Grounded in the retrieved California Wildland-Urban Interface Code — click a citation to read the verbatim passage:
CWUIC § 404.10.2 High relevance — show source text
404.10.2 Clearance of fuel. Defensible space shall be provided around water tank structures, water supply pumps and pump houses in accordance with Section 603.
2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE 4-7
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WILDLAND-URBAN INTERFACE AREA REQUIREMENTS
404.10.3 Standby power. Standby power shall be provided to pumps, controllers and related electrical equipment so that stationary water supply facilities within the wildland-urban interface area that are dependent on electrical power can provide the required water supply. The standby power system shall be in accordance with Section 2702 of the California Building Code and Section 1203 of the California Fire Code . The standby power source shall be capable of providing power for not less than 2 hours.
Exceptions:
- Where approved by the code official, a standby power supply is not required where the primary power service to the stationary water supply facility is underground.
- A standby power supply is not required where the stationary water supply facility serves not more than one singlefamily dwelling.
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CALIFORNIA WILDLAND-URBAN INTERFACE CODE – MATRIX ADOPTION TABLE
CHAPTER 5 – SPECIAL BUILDING CONSTRUCTION REGULATIONS
(Matrix Adoption Tables are nonregulatory, intended only as an aid to the code user. See Chapter 1 for state agency authority and building applications.)
Adopting Agency BSC BSC-
CGSFM Col5 HCD Col7 Col8 DSA Col10 OSHPD Col12 Col13 Col14 Col15 Col16 BSCC DPH AGR DWR CEC CA SL SLC Adopting Agency BSC BSC-
CGT-24 T-19* 1 2 1/AC AC SS 1 1R 2 3 4 5 5 5 5 5 5 5 5 5 Adopt Entire Chapter Adopt Entire Chapter as
amended (amended sections
listed below)X Adopt only those sections that
are listed below[California Code of Regulations,
Title 19, Division 1]Chapter / Section 501.1 X 501.2 X 501.4 – 501.4.1 X 502_Reserved_ X 503.1 X 503. CWUIC § 404.9 High relevance — show source text
May_ 1988.
404.9 Testing and maintenance. Water sources, draft sites, hydrants and other fire protection equipment required by this code shall be subject to periodic tests as required by the code official. Such equipment installed under the provisions of this code shall be maintained in an operative condition at all times and shall be repaired or replaced where defective. Additions, repairs, alterations and servicing of such fire protection equipment and resources shall be in accordance with approved standards.
404.10 Reliability. Water supply reliability shall comply with Sections 404.10.1 through 404.10.3.
404.10.1 Objective. The objective of this section is to increase the reliability of water supplies by reducing the exposure of vegetative fuels to electrically powered systems.
404.10.2 Clearance of fuel. Defensible space shall be provided around water tank structures, water supply pumps and pump houses in accordance with Section 603.
2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE 4-7
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WILDLAND-URBAN INTERFACE AREA REQUIREMENTS
404.10.3 Standby power. Standby power shall be provided to pumps, controllers and related electrical equipment so that stationary water supply facilities within the wildland-urban interface area that are dependent on electrical power can provide the required water supply. The standby power system shall be in accordance with Section 2702 of the California Building Code and Section 1203 of the California Fire Code . The standby power source shall be capable of providing power for not less than 2 hours.
Exceptions:
- Where approved by the code official, a standby power supply is not required where the primary power service to the stationary water supply facility is underground.
- A standby power supply is not required where the stationary water supply facility serves not more than one singlefamily dwelling.
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CALIFORNIA WILDLAND-URBAN INTERFACE CODE – MATRIX ADOPTION TABLE
CHAPTER 5 – SPECIAL BUILDING CONSTRUCTION REGULATIONS
(Matrix Adoption Tables are nonregulatory, intended only as an aid to the code user. See Chapter 1 for state agency authority and building applications.)
CWUIC § 404.5 High relevance — show source text
404.5 Adequate water supply. Fire-flow requirements shall be determined in accordance with Appendix B or BB of the California Fire Code, as applicable.
404.6 Reserved.
404.7 Obstructions. Access to water sources required by this code shall be unobstructed at all times. The fire department shall not be deterred or hindered from gaining immediate access to water source equipment, fire protection equipment or hydrants.
404.8 Identification. Water sources, draft sites, hydrants and fire protection equipment and hydrants shall be clearly identified in a manner approved by the code official to identify location and to prevent obstruction by parking and other obstructions. Each fire hydrant and access to a water supply shall be identified in accordance with one of the following: 1. Where located along a driveway, a reflectorized blue marker with a minimum dimension of 3 inches (73 mm) shall be located on the driveway address sign and mounted on a fire-retardant post. 2. Where located along an access road: 2.2. A reflectorized blue marker with a minimum dimension of 3 inches (73 mm) shall be mounted on a fire-retardant post. The signpost shall be within 3 feet (914 mm) of said fire hydrant with the sign not less than 3 feet (914 mm) nor greater than 5 feet (1524 mm) above ground, in a horizontal position and visible from the driveway. 2.3. As specified in the State Fire Marshal’s Guidelines for Fire Hydrant Markings Along State Highways and Freeways, May 1988.
404.9 Testing and maintenance. Water sources, draft sites, hydrants and other fire protection equipment required by this code shall be subject to periodic tests as required by the code official. Such equipment installed under the provisions of this code shall be maintained in an operative condition at all times and shall be repaired or replaced where defective. Additions, repairs, alterations and servicing of such fire protection equipment and resources shall be in accordance with approved standards.
404.10 Reliability. Water supply reliability shall comply with Sections 404.10.1 through 404.10.3.
404.10.1 Objective. The objective of this section is to increase the reliability of water supplies by reducing the exposure of vegetative fuels to electrically powered systems.
404.10.2 Clearance of fuel. Defensible space shall be provided around water tank structures, water supply pumps and pump houses in accordance with Section 603.
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WILDLAND-URBAN INTERFACE AREA REQUIREMENTS
404.10.3 Standby power. Standby power shall be provided to pumps, controllers and related electrical equipment so that stationary water supply facilities within the wildland-urban interface area that are dependent on electrical power can provide the required water supply. The standby power system shall be in accordance with Section 2702 of the California Building Code and Section 1203 of the California Fire Code . The standby power source shall be capable of providing power for not less than 2 hours.
CWUIC § 3.2 High relevance — show source text
3.2|||||||| |404.4|Hydrants|Y|||507.5|||||| |404.5|Adequate water
supply|Y|||507.3|1275.02(b)||||| |404.6|Reserved|N||||||||| |404.7|Obstructions|Y|||507.5.4|||||| |404.8|Identification|Y||||1275.04(a)||||| |404.9|Testing and
maintenance|Y|||507.5.2|||||| |404.10|Reliability|Y|||507.5.2|||||| |404.10.1|Objective|Y|404.10.1|||||||| |404.10.2|Clearance of fuel|Y|||4907.1|||||| |404.10.3|Standby power|Y|||507.5.2|||||| |Chapter 5|Special building construction regulations|Special building construction regulations|Special building construction regulations|Special building construction regulations|Special building construction regulations|Special building construction regulations|Special building construction regulations|Special building construction regulations|Special building construction regulations|Special building construction regulations| |501|General|Y||701A||||||| |501.1|Scope|Y||701A.3||||||| |501.2|Objective|Y||701A.2||||||| |501.3|Fire-resistance-rated
construction|Y||703.2.1.5||||||| |501.4|Noncombustibility
tests|Y||703.3||||||| |501.4.1|Noncombustible
materials|Y||703.3.1||||||| |502|RESERVED|N||||||||| |503|Ignition-resistant
construction and
material|Y||704A||||||| |503.1|General|Y||701A.3||||||| |503.2|Ignition-resistant
building material|Y||707A.3 #2||||||| |503.2.1|Noncombustible
material|Y||704A.4 #1||||||| |503.2.2|Fire-retardant-
treated wood|Y||704A.4 #2||||||| |503.2.3|Fire-retardant-
treated wood roof
coverings|Y||705A.1||||||| |503.2.4|Other ignition-
resistant building
material|Y||704A.3||||||| |503.2.4.1|Flame spread|Y||704A.3 #1||||||| |503.2.4.2|Flame front|Y||704A.3 #2||||||| |503.2.4.3|Weathering|Y||703A.5.1||||||| |503.2.4.3.1|Evaluation require-
ments for weathering|Y||703A.5.2
703A.5.2.1||||||| |503.2.4.3.2|Wood-plastic
composite materials|Y||703A.6|||||||APPENDIX H-28 2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE
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APPENDIX H—REFERENCED CALIFORNIA DOCUMENTS
CWUIC § 1.5 Medium relevance — show source text
Division 1.5
Section|Title 19,
Division 1
Section|Gov Code
Section|PRC
Section|HSC
Section| |---|---|---|---|---|---|---|---|---|---|---| |Section|Title|Title|Title|Title|Title|Title|Title|Title|Title|Title| |Chapter 4|Wildland-urban interface area requirements|Wildland-urban interface area requirements|Wildland-urban interface area requirements|Wildland-urban interface area requirements|Wildland-urban interface area requirements|Wildland-urban interface area requirements|Wildland-urban interface area requirements|Wildland-urban interface area requirements|Wildland-urban interface area requirements|Wildland-urban interface area requirements| |403.2.5|Address installation,
location, and visibility|Y||||1274.04(a)
1274.04(b)
1274.04(c)
1274.04(d)
1274.04(e)
1274.04(f)||||| |404|Water supply|Y||||1275.02||||| |404.1|General|Y|||507|1275.02(b)||||| |404.2|Required water supply|Y||||1275.02(c)||||| |404.3|Draft sites|Y||||||||| |404.3.1|Access|Y|||507.5.4|||||| |404.3.2|Pumper access points|Y|404.3.2|||||||| |404.4|Hydrants|Y|||507.5|||||| |404.5|Adequate water
supply|Y|||507.3|1275.02(b)||||| |404.6|Reserved|N||||||||| |404.7|Obstructions|Y|||507.5.4|||||| |404.8|Identification|Y||||1275.04(a)||||| |404.9|Testing and
maintenance|Y|||507.5.2|||||| |404.10|Reliability|Y|||507.5.2|||||| |404.10.1|Objective|Y|404.10.1|||||||| |404.10.2|Clearance of fuel|Y|||4907.1|||||| |404.10.3|Standby power|Y|||507.5.2|||||| |Chapter 5|Special building construction regulations|Special building construction regulations|Special building construction regulations|Special building construction regulations|Special building construction regulations|Special building construction regulations|Special building construction regulations|Special building construction regulations|Special building construction regulations|Special building construction regulations| |501|General|Y||701A||||||| |501.1|Scope|Y||701A.3||||||| |501.2|Objective|Y||701A.2||||||| |501.3|Fire-resistance-rated
construction|Y||703.2.1.5||||||| |501.4|Noncombustibility
tests|Y||703.3||||||| |501.4.1|Noncombustible
materials|Y||703.3.CWUIC § A107 Medium relevance — show source text
Exception: Approved public and approved private dumping areas.
A106.2 Ashes and coals. Ashes and coals shall not be placed, deposited or dumped in or on wildland-urban interface areas.
Exceptions:
- In the hearth of an established fire pit, camp stove or fireplace.
- In a noncombustible container with a tightfitting lid, which is kept or maintained in a safe location not less than 10 feet (3048 mm) from nonfire-smart vegetation or structures.
- Where such ashes or coals are buried and covered with 1 foot (305 mm) of mineral earth not less than 25 feet (7620 mm) from nonfire-smart vegetation or structures.
SECTION A107—PROTECTION OF PUMPS AND WATER STORAGE FACILITIES
A107.1 General. The reliability of the water supply shall be in accordance with Sections A107.2 through A107.5.
A107.2 Objective. The intent of this section is to increase the reliability of water storage and pumping facilities and to protect such systems against loss from intrusion by fire.
A107.3 Fuel modification area. Water storage and pumping facilities shall be provided with a defensible space of not less than 30 feet (9144 mm) clear of nonfire-resistive vegetation or growth around and adjacent to such facilities.
Persons owning, controlling, operating or maintaining water storage and pumping systems requiring this defensible space are responsible for clearing and removing nonfire-smart vegetation and maintaining the defensible space on the property owned, leased or controlled by said person.
A107.4 Trees. Portions of trees that extend to within 30 feet (9144 mm) of combustible portions of water storage and pumping facilities shall be removed.
A107.5 Protection of electrical power supplies. Where electrical pumps are used to provide the required water supply, such pumps shall be connected to a standby power source to automatically maintain electrical power in the event of power loss. The standby power source shall be capable of providing power for not less than 2 hours in accordance with Chapter 27 of the California Building Code, Section 1203 of the California Fire Code and the California Electrical Code.
Exception: A standby power source is not required where the primary power service to pumps is underground as approved by the code official.
SECTION A108—LAND USE LIMITATIONS
A108.1 General. Temporary fairs, carnivals, public exhibitions and similar uses must comply with all other provisions of this code in addition to enhanced ingress and egress requirements.
A108.2 Objective. The increased public use of land or structures in wildland-urban interface areas increases the potential threat to life safety. The provisions of this section are intended to reduce that threat.
A108.3 Permits. Temporary fairs, carnivals, public exhibitions or similar uses shall not be allowed in a designated wildland-urban interface area, except by permit from the code official.
Permits shall incorporate such terms and conditions that will reasonably safeguard public safety and property.
A108.4 Access roadways. In addition to the requirements in Section 403, access roadways shall be not less than 24 feet (7315 mm) wide and posted NO PARKING. Two access roadways shall be provided to serve the permitted use area.
Where required by the code official to facilitate emergency operations, approved emergency vehicle operating areas shall be provided.
APPENDIX A-6 2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE
CWUIC § 104.2.2.7 Medium relevance — show source text
Outbuilding 202
Peer Review 104.2.2.7, 202 Permits
Application 105.4 Approval 105.5 Expiration 105.8 Issuance 105.6 Preliminary inspection 105.4.1 Refusal to issue 105.6.1
Required 105.2 Retention 105.9
Revocation 105.10 Validity 105.7 Work exempt from permit 105.3 Placarding as Unsafe 109.3.5.3 Powers and Duties of the Code
Official 104.1
Practical Difficulties 104.2.3 Protection of Pumps and Water Storage Facilities Appendix A, A107
Rafter Tail 202 Referenced Standards 102.4, Chapter 7 Registered Design Professional 104.2.1.2, 104.2.2.6.2, 106.1, 202 Residential Unit 202 Retroactivity 101.4 Ridgelline 202 Road 202 Roof Covering 202 Roof Covering System 202 Roof Coverings, Replacement or Repair of 507
Roof Deck 202
Scope 101 Self-Defense Mechanism Appendix G Service Utilities 111
Slope 202 Spark Arrestors 605 Stop Work Order 113 Storage of Firewood and Combustible Materials 607 Strategic Ridgeline 202 Structure 202
Subdivision 202
Technical Assistance 104.2.1 Temporary Uses, Equipment and Systems 107 Tree Crown 202
Trees 603.4.2
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INDEX
Undeveloped Ridgeline 202 Unenclosed Accessory Structure 202
Vegetation Control Appendix A, A102 Vegetation management compliance 106.4 Vegetation Management Plan Appendix B Vents 504.10
Vertical Curve 202
Water Supply Adequate water supply 404.5 Applicability 402 Draft sites 404.3 Hydrants 404.4 Identification 404.8
Obstructions 404.7 Reliability 404.10 Required water supply 404.2 Subdivisions 402.1 Testing and maintenance 404.9 Water sources 404.2
Wildfire 202
Wildland 202
Wildland-Urban Interface Area 202
Wildland-Urban Interface Area Designations 302 Declaration 302.1
Mapping 302.2 Review 302.3
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HISTORY NOTE APPENDIX
2025 California Wildland-Urban Interface Code California Code of Regulations, Title 24, Part 7
HISTORY:
CWUIC § 12-2 Medium relevance — show source text
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12-2 2025 CALIFORNIA FIRE CODE
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12 ENERGY SYSTEMS
User notes:
About this chapter: Chapter 12 was added to address the current energy systems found in this code, and is provided for the introduction of a wide range of systems to generate and store energy in, on and adjacent to buildings and facilities. The expansion of such energy systems is related to meeting today’s energy, environmental and economic challenges. Ensuring appropriate criteria to address the safety of such systems in building and fire codes is an important part of protecting the public at large, building occupants and emergency responders. More specifically, this chapter addresses standby and emergency power, portable generators, photovoltaic systems, fuel cell energy systems and energy storage systems.
SECTION 1201—GENERAL
1201.1 Scope. The provisions of this chapter shall apply to the installation, operation, maintenance, repair, retrofitting, testing, commissioning and decommissioning of energy systems used for generating or storing energy, including but not limited to energy storage systems under the exclusive control of an electric utility or lawfully designated agency. It shall not apply to equipment associated with the generation, control, transformation, transmission, or distribution of energy installations that is under the exclusive control of an electric utility or lawfully designated agency. Energy storage systems regulated by Section 1207 shall comply with this chapter, as appropriate, and NFPA 855.
1201.2 Electrical wiring and equipment. Electrical wiring and equipment used in connection with energy systems shall be installed and maintained in accordance with this chapter, Section 603 and the California Electrical Code.
1201.3 Mixed system installation. Where mixed systems are approved, the aggregate nameplate kWh energy of all energy storage systems in a fire area shall not exceed the maximum quantity specified for any of the energy systems in this chapter. Where required by the fire code official, a hazard mitigation analysis shall be provided and approved in accordance with Section 104.2.2 to evaluate any potential adverse interaction between the various energy systems and technologies.
SECTION 1202—DEFINITIONS
1202.1 Definitions. The following terms are defined in Chapter 2:
BATTERY SYSTEM, STATIONARY STORAGE.
BATTERY TYPES.
CAPACITOR ENERGY STORAGE SYSTEM.
CRITICAL CIRCUIT.
EMERGENCY POWER SYSTEM.
ENERGY STORAGE MANAGEMENT SYSTEMS.
ENERGY STORAGE SYSTEM (ESS).
ENERGY STORAGE SYSTEM, ELECTROCHEMICAL.
ENERGY STORAGE SYSTEM, MOBILE.
ENERGY STORAGE SYSTEM, WALK-IN UNIT.
ENERGY STORAGE SYSTEM CABINET.
ENERGY STORAGE SYSTEM COMMISSIONING.
ENERGY STORAGE SYSTEM DECOMMISSIONING.
FUEL CELL POWER SYSTEM, STATIONARY.
PORTABLE GENERATOR.
STANDBY POWER SYSTEM.
SECTION 1203—EMERGENCY AND STANDBY POWER SYSTEMS
1203.1 General. Emergency power systems and standby power systems required by this code or the California Building Code shall comply with Sections 1203.1.1 through 1203.1.9.
1203.1.1 Stationary generators. Stationary emergency and standby power generators required by this code shall be listed in accordance with UL 2200.
2025 CALIFORNIA FIRE CODE 12-3
CWUIC § 2702.1.4 Medium relevance — show source text
[F] 2702.1.4 Load transfer. Emergency power systems shall automatically provide secondary power within 10 seconds after primary power is lost, unless specified otherwise in this code. Standby power systems shall automatically provide secondary power within 60 seconds after primary power is lost, unless specified otherwise in this code.
[F] 2702.1.5 Load duration. Emergency power systems and standby power systems shall be designed to provide the required power for a minimum duration of 2 hours without being refueled or recharged, unless specified otherwise in this code.
[F] 2702.1.6 Uninterruptable power source. An uninterrupted source of power shall be provided for equipment where required by the manufacturer’s instructions, the listing, this code or applicable referenced standards.
[F] 2702.1.7 Interchangeability. Emergency power systems shall be an acceptable alternative for installations that require standby power systems.
[F] 2702.1.8 Group I-2 occupancies. In Group I-2 occupancies located in flood hazard areas established in Section 1612.3, where new essential electrical systems are installed, and where new essential electrical system generators are installed, the systems and generators shall be located and installed in accordance with ASCE 24. Where connections for hookup of temporary generators are provided, the connections shall be located at or above the elevation required in ASCE 24.
[F] 2702.2 Where required. Emergency and standby power systems shall be provided where required by Sections 2702.2.1 through 2702.2.19.
[F] 2702.2.1 Ambulatory care facilities. Essential electrical systems for ambulatory care facilities shall comply with Section 422.6.
[F] 2702.2.2 Elevators and platform lifts. Standby power shall be provided for elevators and platform lifts as required in Sections 1009.4.1, 1009.5, 3003.1, 3007.8 and 3008.8.
2025 CALIFORNIA BUILDING CODE 27-3
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
ELECTRICAL
[F] 2702.2.3 Emergency responder communication coverage systems. Standby power shall be provided for in-building 2-way emergency responder communication coverage systems required in Section 918 and the California Fire Code . The standby power supply shall be capable of operating the in-building 2-way emergency responder communication coverage system at 100-percent system operation capacity for a duration of not less than 12 hours.
[F] 2702.2.4 Emergency voice/alarm communication systems. Standby power shall be provided for emergency voice/alarm communication systems in accordance with NFPA 72.
[F] 2702.2.5 Exhaust systems. Standby power shall be provided for common exhaust systems for domestic kitchens located in multistory structures as required in Section 505.5 of the California Mechanical Code . Standby power shall be provided for common exhaust systems for clothes dryers located in multistory structures as required in Section 504.11 of the California Mechanical Code and Section 614.11 of the International Fuel Gas Code .
CWUIC § 1203.1.4 Medium relevance — show source text
1203.1.4 Load transfer. Emergency power systems shall automatically provide secondary power within 10 seconds after primary power is lost, unless specified otherwise in this code. Standby power systems shall automatically provide secondary power within 60 seconds after primary power is lost, unless specified otherwise in this code.
1203.1.5 Load duration. Emergency power systems and standby power systems shall be designed to provide the required power for a minimum duration of 2 hours without being refueled or recharged, unless specified otherwise in this code.
1203.1.5.1 High-rise buildings and Group I-2 occupancies having occupied floors located more than 75 feet above the lowest floor level having building access. Emergency power systems and standby power systems shall be designed to provide the required power for a minimum duration of 6 hours without being refueled or recharged. The minimum required fuel supply shall be maintained at all times.
1203.1.6 Uninterruptable power source. An uninterrupted source of power shall be provided for equipment where required by the manufacturer’s instructions, the listing, this code or applicable referenced standards.
1203.1.7 Interchangeability. Emergency power systems shall be an acceptable alternative for installations that require standby power systems.
1203.1.8 Group I-2 occupancies. In Group I-2 occupancies located in flood hazard areas established in Section 1612.3 of the California Building Code where new essential electrical systems are installed, and where new essential electrical system generators are installed, the systems and generators shall be located and installed in accordance with ASCE 24. Where connections for hook up of temporary generators are provided, the connections shall be located at or above the elevation required in ASCE 24.
1203.1.9 Maintenance. Existing installations shall be maintained in accordance with the original approval and Section 1203.4.
1203.2 Where required. Emergency and standby power systems shall be provided where required by Sections 1203.2.1 through 1203.2.19.
1203.2.1 Ambulatory care facilities. Essential electrical systems for ambulatory care facilities shall be in accordance with Section 422.6 of the California Building Code .
1203.2.2 Elevators and platform lifts. Standby power shall be provided for elevators and platform lifts as required in Sections 604.3, 1009.4.1 and 1009.5.
1203.2.3 Emergency responder communication coverage systems. Standby power shall be provided for in-building, two-way emergency responder communication coverage systems as required in Section 510.4.2.3. The standby power supply shall be capable of operating the in-building, two-way emergency responder communication coverage system at 100-percent system operation capacity for a duration of not less than 12 hours.
1203.2.4 Emergency voice/alarm communication systems. Standby power shall be provided for emergency voice/alarm communication systems in accordance with NFPA 72.
1203.2.5 Exhaust ventilation. Standby power shall be provided for mechanical exhaust ventilation systems as required in Section 1207.6.1.2.1. The system shall be capable of powering the required load for a duration of not less than 2 hours.
1203.2.6 Exit signs. Emergency power shall be provided for exit signs as required in Section 1013.6.3. The system shall be capable of powering the required load for a duration of not less than 90 minutes.
CWUIC § 4.1 Medium relevance — show source text
4|Combustible
materials|N||||||||| |A105.4.1|Individual piles|N||||||||| |A105.4.2|Separation|N||||||||| |A106|Dumping|N||||||||| |A106.1|Waste material|N||||||||| |A106.2|Ashes and coals|N||||||||| |A107|Protection of pumps
and water storage
facilities|N||||||||| |A107.1|General|N||||||||| |A107.2|Objective|N||||||||| |A107.3|Fuel modification
area|N||||||||| |A107.4|Trees|N||||||||| |A107.5|Protection of electri-
cal power supplies|N||||||||| |A108|Land use limitations|N||||||||| |A108.1|General|N||||||||| |A108.2|Objective|N||||||||| |A108.3|Permits|N||||||||| |A108.4|Access roadways|N||||||||| |A109|Referenced standards|N||||||||| |A109.1|General|N|||||||||APPENDIX H-34 2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
APPENDIX H—REFERENCED CALIFORNIA DOCUMENTS
2025 CWUIC—continued Col2 Adopted
Yes/NoIWUIC
SectionCBC
SectionCFC
SectionTitle 14,
Division 1.5
SectionTitle 19,
Division 1
SectionGov Code
SectionPRC
SectionHSC
SectionSection Title Title Title Title Title Title Title Title Title Title Appendix B Vegetation management plan Vegetation management plan Vegetation management plan Vegetation management plan Vegetation management plan Vegetation management plan Vegetation management plan Vegetation management plan Vegetation management plan Vegetation management plan B101 General N B101.1 Scope N B101.2 Plan content N B101.3 Fuel modification N Appendix C Community Wildland-Urban Interface (WUI) Fire Hazard Evaluation Framework Community Wildland-Urban Interface (WUI) Fire Hazard Evaluation Framework Community Wildland-Urban Interface (WUI) Fire Hazard Evaluation Framework Community Wildland-Urban Interface (WUI) Fire Hazard Evaluation Framework Community Wildland-Urban Interface (WUI) Fire Hazard Evaluation Framework Community Wildland-Urban Interface (WUI) Fire Hazard Evaluation Framework Community Wildland-Urban Interface (WUI) Fire Hazard Evaluation Framework Community Wildland-Urban Interface (WUI) Fire Hazard Evaluation Framework **_Community Wildland-Urban Interface (WUI) CWUIC § 4.1 Medium relevance — show source text
2025 CALIFORNIA WILDLAND-URBAN INTERFACE CODE APPENDIX A-5
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
APPENDIX A—GENERAL REQUIREMENTS
A105.3 Explosives. Explosives shall not be possessed, kept, stored, sold, offered for sale, given away, used, discharged, transported or disposed of within wildland-urban interface areas, except by permit from the code official.
A105.4 Combustible materials. Outside storage of combustible materials such as, but not limited to, wood, rubber tires, building materials or paper products shall comply with the other applicable sections of this code and this section. A105.4.1 Individual piles. Individual piles shall not exceed 5,000 square feet (465 m [2] ) of contiguous area. Piles shall not exceed 50,000 cubic feet (1416 m [3] ) in volume or 10 feet (3048 mm) in height.
A105.4.2 Separation. A clear space of not less than 40 feet (12 192 mm) shall be provided between piles. The clear space shall not contain combustible material or nonfire-smart vegetation.
SECTION A106—DUMPING
A106.1 Waste material. Waste material shall not be placed, deposited or dumped in wildland-urban interface areas or in, on or along trails, roadways or highways or against structures in wildland-urban interface areas .
Exception: Approved public and approved private dumping areas.
A106.2 Ashes and coals. Ashes and coals shall not be placed, deposited or dumped in or on wildland-urban interface areas.
Exceptions:
- In the hearth of an established fire pit, camp stove or fireplace.
- In a noncombustible container with a tightfitting lid, which is kept or maintained in a safe location not less than 10 feet (3048 mm) from nonfire-smart vegetation or structures.
- Where such ashes or coals are buried and covered with 1 foot (305 mm) of mineral earth not less than 25 feet (7620 mm) from nonfire-smart vegetation or structures.
SECTION A107—PROTECTION OF PUMPS AND WATER STORAGE FACILITIES
A107.1 General. The reliability of the water supply shall be in accordance with Sections A107.2 through A107.5.
A107.2 Objective. The intent of this section is to increase the reliability of water storage and pumping facilities and to protect such systems against loss from intrusion by fire.
A107.3 Fuel modification area. Water storage and pumping facilities shall be provided with a defensible space of not less than 30 feet (9144 mm) clear of nonfire-resistive vegetation or growth around and adjacent to such facilities.
Persons owning, controlling, operating or maintaining water storage and pumping systems requiring this defensible space are responsible for clearing and removing nonfire-smart vegetation and maintaining the defensible space on the property owned, leased or controlled by said person.
A107.4 Trees. Portions of trees that extend to within 30 feet (9144 mm) of combustible portions of water storage and pumping facilities shall be removed.
Frequently asked questions
When exactly does the standby power requirement apply?
It applies to stationary water supply facilities within the WUI that are dependent on electrical power, per § 404.10.3; if the facility is electrically dependent, standby power is required unless an exception applies.
How long must the standby power run?
The standby power source must be capable of providing power for not less than 2 hours, per § 404.10.3.
Do I always need to clear 30 feet around tanks and pump houses?
§ 404.10.2 requires defensible space in accordance with Section 603; Appendix A (A107) recommends 30 feet as a prescriptive fuel modification area around water storage and pumping facilities. Confirm whether your jurisdiction enforces Appendix A.
Can a portable generator meet the requirement?
The CWUIC requires a standby power system in accordance with CBC §2702 and CFC §1203. Portable generators may be acceptable if they meet the referenced standards and provide automatic or approved means to ensure operation for ≥ 2 hours; verify with the code official. § 404.10.3.
Is standby power required if my service is underground?
Not necessarily — § 404.10.3 Exception 1 allows the code official to waive the standby power requirement where the primary power service is underground, if approved. Get written approval from the code official.
More in California Wildland-Urban Interface Code
- Administration and Definitions
- Board of Appeals, Administration & Enforcement (permits, code official duties, appeals process)
- Wildland‑Urban Interface Area Designation & Mapping
- Fire Service Access & Water Supply (fire apparatus roads, driveways, hydrants, draft sites, standby power)
- Wildland‑Urban Interface Area Requirements (access, water, premises identification, key boxes)
- Referenced Standards & Test Methods
- Special Building Construction Regulations (ignition‑resistant construction, roof/vent/assembly requirements)
- Appendices and Model Ordinances (vegetation plans, severity‑zone adoption, home‑hardening guidance)
- Fire Protection Requirements (fire protection plans, systems, safety element provisions)
- Referenced California Documents & Matrix (CCR/Title 14 & 19 cross‑references, statutory references)
- Vegetation Management & Defensible Space (vegetation plans, maintenance, fire‑smart characteristics)
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