2025 California
Residential Code
Complete guide to all residential building code changes effective January 1, 2026. Based on the IRC 2024 with California-specific amendments.
Official Resources
In This Guide
Major Update: The 2025 Energy Code is approximately 30% more restrictive than 2022. It introduces new metrics, expands heat pump requirements, and mandates battery storage with PV systems.
Key Changes from 2022
| Requirement | 2022 Code | 2025 Code |
|---|---|---|
| Energy Metric | Time Dependent Valuation (TDV) | Long-term System Cost (LSC) |
| Heat Pump - Space Heating | Prescriptive baseline | Required for standard designs |
| Heat Pump - Water Heating | Prescriptive baseline | Required for standard designs |
| Battery Storage | Not required | Required with PV systems |
| Window U-Factor | 0.30 - 0.32 | Lower requirements by zone |
| Insulation | Standard R-values | Enhanced R-values required |
Heat Pump Requirements
- Heat pump capacity must meet minimum CBC heating requirements without supplementary heat
- Thermostat must display outdoor air temperature and lock out supplementary heat when OAT is above 35°F
- Maximum allowable capacities established for supplementary heating systems
Electric-Ready Requirements
For systems using gas or propane furnaces:
240V dedicated branch circuit within 3' of furnaceMinimum 30 amp conductorsReserved space for double pole breakerMarked "For Future 240V Use"Base Code: The 2025 California Electrical Code is based on NFPA 70 (NEC) 2023 with California amendments.
Key Changes
Expanded GFCI Requirements
GFCI protection now required in more areas beyond kitchens and bathrooms. Any remodel adding outlets likely needs GFCI in additional locations.
Dual-Function Protection
Some circuits now require both AFCI and GFCI protection. Combination breakers available but more expensive.
Solar Rapid Shutdown
Rapid shutdown systems must now be integrated directly into modules or arrays. Enhanced safety for first responders.
Battery Storage Safety
New requirements for battery system spacing, labeling, and fire safety design. AC-coupled systems require transfer switches.
EV-Ready Requirements
Trade size 1 (1-inch) raceway from panel to garage, 208/240V capableAll new residential construction must be EV-ready with conduit capable of supporting a Level 2 charger.
View Full 2025 California Electrical CodeBase Code: The 2025 California Plumbing Code is based on the Uniform Plumbing Code (UPC) 2024 with California amendments.
Key Changes
| Item | 2022 | 2025 |
|---|---|---|
| PEX Acceptance | Limited use | Widely accepted |
| Lead Content | Low lead | Max 0.25% |
| Water Closet Max | 1.28 gpf | 1.28 gpf (unchanged) |
| CPVC for Potable Water | Permitted | Not permitted (OSHPD 1-5) |
Water Conservation Requirements
CALGreen (Part 11) mandates strict fixture flow rates:
1.28 gpf maximum1.8 gpm maximum1.2 gpm maximumBase Code: The 2025 California Mechanical Code is based on the Uniform Mechanical Code (UMC) 2024.
Key Changes
Duct Sealing - Seal Class A
All ducts, regardless of pressure classification, must be sealed to Seal Class A. This includes all transverse joints, longitudinal seams, and duct wall penetrations.
TAB Certification Required
All Testing, Adjusting, and Balancing (TAB) and Duct Leakage Testing must be performed by a technician certified by an approved agency.
Heat Pump Sizing
Sizing and equipment selection requirements ensure heat pumps meet design heating loads without supplementary electric resistance or gas.
Ventilation Standards
Strengthened ventilation requirements for heat pump water heaters and improved indoor air quality standards.
Major Restructure: California has created a new standalone Wildland-Urban Interface Code (CWUIC) based on the International WUI Code. This consolidates requirements previously scattered across CBC Chapter 7A, CRC Section R337, and California Fire Code Chapter 49.
What Changed
| Previous Location | 2025 Location |
|---|---|
| CBC Chapter 7A | CWUIC Chapter 5 |
| CRC Section R337 | CWUIC Chapter 5 (R337 Repealed) |
| CFC Chapter 49 | CWUIC (Consolidated) |
Key Requirements
- WUI Vents: All ventilation openings must be covered with Wildfire Flame and Ember Resistant vents approved by the California State Fire Marshal or tested to ASTM E2886
- Defensible Space: 100 feet of fuel modification required around buildings (or to property line)
- Fire Sprinklers: Required in all new single-family homes (since 2011, unchanged)
Applies To: All Fire Hazard Severity Zones in State Responsibility Areas (SRA) and Very High Fire Hazard Severity Zones in Local Responsibility Areas (LRA).
California Green Building Standards Code is the nation's first mandatory green building code. The 2025 cycle strengthens requirements for water use, electrification, material efficiency, and embodied carbon.
Single-Family EV Requirements (Unchanged)
Good news: No changes for single-family and townhouses from 2022.
Trade size 1 (1-inch) raceway from panel to garage for 208/240V Level 2 capableMultifamily Changes (3+ Units)
Assigned Parking
100% EV coverage - every assigned stall must include a low-power Level 2 receptacle (208/240V)
Common Parking
At least 1 receptacle per unit, plus 25% of extra common spaces must have installed Level 2 chargers
Water Conservation
CALGreen works in conjunction with the Plumbing Code to mandate strict water efficiency:
- All fixtures must meet strict flow rate limits
- Graywater system provisions supported
- Rainwater capture encouraged
Structural & Administrative Changes
| Section | 2022 | 2025 Change |
|---|---|---|
| Vapor Retarder | 10-mil requirement | 6-mil requirement |
| Private Elevators | No specific section | New R323.1.1 added |
| Light & Ventilation (R303) | Combined section | Now R325 - separated into R325.1.1 and R325.1.2 |
| Care Facilities | General provisions | R322.3 - CBC 11B accessibility required |
| PV/Energy Storage | California-specific sections | Model code sections adopted (same requirements) |
| Existing Building Stairs | Limited provisions | New section added |
Definition Updates
Multiple definitions were amended to eliminate references to IRC chapters not adopted in California. Existing California definitions were repealed and replaced with model code definitions containing the same language.
Chapter 3 Renumbering
Multiple sections in Building Planning (Chapter 3) were renumbered to align with significant numbering changes in the IRC 2024 model code. Review your references carefully.
Frequently Asked Questions
Common questions about the 2025 California Residential Code changes
When does the 2025 California Residential Code take effect?
The 2025 California Residential Code (CRC) takes effect January 1, 2026. Building permits filed before this date may use the 2022 code cycle, while permits filed on or after January 1, 2026 must comply with the new requirements.
What are the biggest changes in the 2025 CRC?
The most significant changes include: expanded heat pump requirements for climate zones 1-16, updated EV charging provisions (now in residential code), enhanced energy efficiency standards with stricter envelope requirements, new WUI fire safety regulations from the 2022 CWUIC, and updated accessibility standards.
Do I need a heat pump for my new home under the 2025 code?
For climate zones 1-16, the 2025 CRC requires heat pumps as the primary space heating system in newly constructed single-family and low-rise multifamily buildings. This expands from the 2022 requirement which only covered certain climate zones. Heat pump water heaters continue to be required statewide.
What is the base model code for the 2025 CRC?
The 2025 California Residential Code is based on the IRC 2024 (International Residential Code 2024), with California-specific amendments. This represents an update from the 2022 CRC which was based on the IRC 2021.
How can I ensure my plans comply with the 2025 CRC?
You can use AI-powered tools like PlanCheckSolver to automatically check your building plans against the 2025 CRC requirements. This catches compliance issues early, before costly rework during construction. Our system validates architectural, structural, MEP, and energy code requirements in minutes.
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