California Building Code Watch
The Errata Blog
California Title 24 changes mid-cycle — through errata and supplements, not just at the three-year adoption. We read all ten code books every month and write up what actually changed and what it means for your plan reviews.
0.35, not 35: reading CALGreen's WS-2 water-use worksheet
CALGreen's WS-2 water-use worksheet carried a 35 gpm flow rate where it meant 0.35 — here's how the reduction credit and its lavatory rates actually work.
The zone crosswalk behind unvented-attic insulation (Table 1202.3.1)
The January 2026 errata added California Energy Code Zone 7 to Table 1202.3.1's IECC 3 (marine) row, fixing the lookup that tells a coastal unvented-attic designer which condensation-control percentage applies.
A2L machinery rooms: which Table 1102.3 column trips which detector
California's January 2026 Mechanical Code errata corrected the Table 1102.3 RCL and LFL values that drive A2L machinery-room detector setpoints and the 25%-of-LFL de-energize trip.
When 39,000 should be 390,000: the Table 5003.11.2 flammable-gas fix
California's January 2026 Fire Code errata corrected Table 5003.11.2's sprinklered flammable-gas limit from 39,000 to 390,000 cubic feet — and the 2:1 sprinkler math proves the fix is right.
Washington's housing bill won't change your Monday — but the money might
The 21st Century ROAD to Housing Act bundles roughly 50 provisions — but for California builders and cities, two are worth acting on now: competitive grant money for jurisdictions that streamline permitting, and a cheaper path for factory-built homes.
Which ASCE 41 edition applies to your California retrofit?
The January 2026 errata put three editions of ASCE/SEI 41 side by side in the Existing Building Code's Chapter 16 — here's which one your retrofit actually has to use.
Designing in Wood? The 2025 CRC Runs on NDS-2024
The January 2026 errata change-barred CRC Chapter 44's wood-design reference, confirming the 2025 code runs on NDS-2024 with its 2024 Supplement — the edition your reference values and connection calcs must come from.
Which edition am I designing to? The errata edited the standards chapters
The January 2026 errata reworked the referenced-standards chapters in three Title 24 books — the chapter where a bare standard name becomes the edition you're legally bound to.
Ember-resistant vents and eaves: the wildfire tests the code just edited
The January 2026 California Residential Code errata quietly amended the two ASTM wildfire test methods that decide whether your attic vents and eaves are legal in a Fire Hazard Severity Zone.
Solar roof-load rules moved: CBC 1607.22 (was 1607.14.3)
California's rooftop-PV live-load provisions moved from CBC 1607.14.3 to 1607.22 in the January 2026 errata — the load values didn't change, only the citation.
Stucco on the California coast: which counties now owe a rainscreen
The January 2026 errata rewrote R703.7.3 so a hard list of coastal counties — not a fuzzy climate label — decides whether your stucco job needs a 3/16-inch rainscreen behind the lath.
Group I-2 Is Risk Category IV: the 'Condition 2' Table Fix
California's Group I-2 occupancies have no 'Conditions,' so the January 2026 errata deleted the stray 'Condition 2' from the Risk Category IV table — leaving the whole class squarely in Risk Category IV.
Can an ADU's front door have a deadbolt? What CBC 1010.2.4 says
California's egress code bans manual bolts on doors in the path of travel — except on a dwelling or sleeping unit's single exit door, where a thumb-turn deadbolt is fine but a key-both-sides lock is not.
Door or glazed door? The 25% line that flips your Title 24 rules
The Energy Code splits openings at a hard line — under 25% glazed it's a door, 25% or more and it's a glazed door held to fenestration product requirements — and the January 2026 errata corrected that definition.
The A2L numbers California just fixed — and your heat-pump plan check
California's January 2026 Mechanical Code errata corrected the Table 1102.3 RCL and LFL values for A2L refrigerant blends — the same numbers that size a charge and set a detector's trip point.
Electric-Ready Wiring Is Code: What CEC 422.3 Means for New Homes
California's Electrical Code now requires new single-family and multifamily homes to be wired electric-ready — and the January 2026 errata fixed the Energy Code section numbers you design and plan-check against.
California has no Group I-2 'Condition' — the 2026 errata says so
In California the smoke compartment — not a model-code I-2 'Condition' — governs hospital design, and the January 2026 errata scrubbed the leftover Condition tags out of the Building and Fire Codes.
Reroofing in a fire hazard zone? CBC 705A no longer exists
The wildfire roofing rules didn't change this cycle — they moved out of the Building Code into the standalone WUI Code, so a permit citing CBC 705A now points at nothing.
Stop citing Government Code 65852.2 on ADU plans — it's 66313 now
California moved its entire ADU statute out of Government Code §65852.2, and the January 2026 errata corrected the stale definition cross-reference to §66313 in six Title 24 code books at once.
The above-ground pool "exemption" that doesn't exist in California
A widely repeated pool-industry belief — that a tall-walled above-ground pool with a removable ladder is its own barrier — has no basis in California's Swimming Pool Safety Act.
Every change in the January 2026 Title 24 errata — all 118, in one place
The complete, section-by-section list of the January 2026 errata to the 2025 California Building Standards Code — every change in all 10 affected books, with the items that move real review logic flagged.
The code book had a typo that was off by 100x
California's 2025 codes shipped with bugs — including a CALGreen water-flow value off by 100x — and the state has now patched them mid-cycle with buff-colored replacement pages.
Your title block is citing sections that moved
The January 2026 Title 24 errata moved and re-pointed code sections that show up in general notes, PV details, and reroof notes — here's what to find and fix.
What landed in the January 2026 Title 24 errata
A field guide to the January 2026 batch: which books changed, what’s a harmless rename, and the handful of items that actually change how a plan gets reviewed.
The ADU sprinkler exemption is now written into the code itself
For years the ADU fire-sprinkler exemption lived only in the Government Code. The January 2026 errata restates it directly in the Residential Code — closing a common plan-check foot-fault.