The code book had a typo that was off by 100x

Here's a thing nobody tells you in code-update seminars: the code book ships with bugs. Not policy disagreements — actual typos. A decimal point in the wrong place. A reference pointing at the wrong section. A number that's off by a factor of three, or ten, or, in one delightful case this cycle, 100 times.

The 2025 Triennial Edition of Title 24 took effect statewide on January 1, 2026. And on March 3, 2026, the California Building Standards Commission published Information Bulletin 26-01, the official errata notice — corrections that are themselves backdated to be effective and enforceable as of that January 1 date. In other words: the code you've been working from since New Year's already had a patch in flight.

Let's look at what actually got fixed, because some of these are genuinely funny until the moment they aren't.

The 100x one

In CALGreen (Part 11), Chapter 8, there's a water-efficiency compliance form — Worksheet WS-2, Water Use Reduction. Footnote 4 to that worksheet specified a fixture flow rate. The first printing said 35 gpm. The corrected printing says 0.35 gpm.

Verified against the 2025 CALGreen errata (effective January 2026): Footnote 4 to Worksheet WS-2 (Water Use Reduction) corrected to require 0.35 gpm instead of 35 gpm.

Thirty-five gallons per minute is roughly a fire hose. A lavatory faucet in California maxes out around half a gallon per minute. So on a water-efficiency worksheet — the one whose entire job is to prove you're saving water — the published number was off by two orders of magnitude in the wrong direction. Anybody filling that form by the letter would have been reverse-engineering a comedy.

The 3x one

Over in the Existing Building Code (Part 10), §1504.1.4.1, a roof-panel spec listed a thickness of 15/16 inch. The corrected value is 5/16 inch — carried in from the 2024 IEBC errata. That's not a rounding nudge; it's a 3x difference in a structural dimension. The kind of number a plan checker would (correctly) flag, or a fabricator would (incorrectly) build to, depending on which printing was open on the desk.

The one that actually matters for safety

Not every erratum is good for a laugh. The Mechanical Code (Part 4), Table 1102.3 carries the RCL and LFL values — refrigerant concentration limits and lower flammability limits — for the new A2L "mildly flammable" refrigerant blends now showing up in heat pumps (R-444A through R-455A). Those are the quantity limits that keep a refrigerant leak from becoming an ignition problem.

The first printing carried errors that traced back to 2019 ASHRAE Standard 34 data and its addenda. The corrected table aligns the values with the IAPMO TIA (UMC 003-24). When the wrong number is a safety limit on a flammable gas, "typo" stops being cute.

The quiet ones

The Energy Code (Part 6) got its BESS capacity factors corrected in Tables 140.10-B and 170.2-V — the battery-storage sizing factors for a handful of building types and climate zones. And as a bonus from the Fire Code (Part 9), Table 5003.11.2 bumped a Category 1B gaseous max allowable quantity from 39,000 to 390,000 cubic feet — there's your other 10x of the cycle.

How the state ships a patch

Here's the part worth internalizing. California doesn't reprint the whole code when it finds these. It issues buff-colored replacement pages — literally tan-tinted sheets you pull and swap into a binder — and the BSC labels the whole batch "non-substantive errata." Which is a wonderfully bureaucratic way to describe a number that moved 100x. "Non-substantive" here means no new policy, not no real change; the requirement was always 0.35 gpm — the page just finally says so.

The catch: the corrected PDFs are scattered across three different hosts — dgs.ca.gov for the bulletin, iccsafe.org for several parts, and iapmo.org for the Mechanical and Plumbing packets. There's no single download.

So, how do you know which printing you're holding?

• Print and binder holders: confirm the buff replacement pages are actually inserted. A pristine first printing is, quietly, wrong.
• Online and PDF users: pull the errata for each Part from the hosts above and check the dated corrections against your copy. Each Part's errata is the one effective January 2026.

This is the unglamorous reality of working from code: the document is a living artifact that gets bugfixes mid-cycle, and the version you're reading matters as much as the section number. When in doubt, confirm the current text with your authority having jurisdiction.

What CrossBeam does with it

CrossBeam tracks these corrections and reviews plans against the current code text — the version with January 2026 errata applied, not the first printing. So a submittal isn't measured against a 35-gpm typo or a 15/16-inch panel that no longer exists in the code as corrected.