The state code is the floor: why local amendments drive plan-check corrections
Two projects under the same state code edition, ten miles apart, get different correction lists. The reason is the amendment layer, and the precedence rules that decide which text wins when the state and the city disagree.
Ask what building code a project is under and you will usually get a state answer: the 2025 California Building Code, the 2021 IBC, the 2020 New York State code. That answer is correct and it is also incomplete in the way that costs projects weeks. The state edition is a floor. What a plan checker reviews against is that floor plus whatever the city or county adopted on top of it, and the ordinance on top is where most correction lists actually come from.
We maintain an adoption map covering every U.S. state and territory plus 78 cities and counties, because our review engine cannot cite a code section without first resolving which code governs. Building it surfaced a pattern worth writing down: the amendment layer is not a footnote on the state code. It is a different question with different answers, and it is the question most teams skip.
Three ways a local amendment can relate to the state code
"The city amended the code" describes at least three legally distinct situations, and they do not resolve the same way. Getting the relationship wrong is how a team ends up designing to text that does not govern.
| Relationship | What governs | Practical effect |
|---|---|---|
| More restrictive | The stricter of the state or local provision | You must satisfy both. In California this is the default posture for building standards under Health & Safety Code 17958.5, which lets a city adopt stricter standards on an express local finding. |
| Replaces | The local text, outright | Reading the state section tells you nothing useful. The local ordinance is the operative text for that provision in that jurisdiction. |
| Adds | State text plus local additions | The state requirement still applies unchanged; the city has layered extra requirements on top of it. |
A fourth case runs the other direction: a state statute that preempts the local rule. In California, ADU law (Gov. Code 66310 et seq.), SB 9 lot splits and two-unit developments (Gov. Code 65852.21 and 66411.7), and the State Density Bonus Law (Gov. Code 65915) each override conflicting local zoning. Those carve-outs are the reason a local standard someone quotes at a counter is sometimes simply not enforceable against your project.
Why this shows up as corrections rather than as design changes
The amendment layer is hard to research at the moment you need it. State editions are published, indexed, and searchable. Local amendments live in a municipal code hosted on one of several third-party platforms, are organized by the city's own title-and-chapter scheme rather than the code's, and are amended by ordinance on a schedule nobody outside that city tracks. A team that would never guess at an occupancy classification will routinely guess at whether a city amended its fire-access requirements, because checking takes an afternoon and the deadline was yesterday.
So the amendment gets discovered by the plan checker instead of the designer. That is the expensive ordering. A correction found in design is a redraw; the same correction found in review is a resubmittal, and a resubmittal is a new position in the queue.
The version question is a second trap
Code editions change on a cycle, and the changeover does not respect project schedules. California moved to the 2025 Title 24 with the 2022 edition still governing applications complete on or before December 31, 2025. Two otherwise identical sets, submitted a week apart across that line, are reviewed against different codes.
The governing edition usually attaches to the date the application was deemed complete, not the date you drew the sheets and not the date review begins. If a project straddles a changeover, that date is worth confirming in writing with the department before you assume which edition applies.
What to actually do
- Resolve the jurisdiction before the edition. "Los Angeles" is a city and a county with different amendment sets, and an unincorporated address inside a county is reviewed by the county, not the nearest city.
- Pull the local amendments for the disciplines your project actually triggers, not all of them. A single-story addition does not need the high-rise amendments.
- For each amendment, establish the relationship: does it replace the state text, add to it, or is it a stricter version you satisfy by meeting both?
- Check for a state preemption before you accept a local zoning constraint on an ADU, a lot split, or a density-bonus project.
- Confirm the edition against the application-complete date, especially within a year of a changeover.
We published the adoption layer of this at /code: the adopted edition by discipline for every state, and the local amendments for the cities and counties we have researched, with the ordinance citations. It is the same map our plan review resolves against, so what is on those pages is what a review would actually apply.
Catch the corrections before the city does
Architechtura runs an automated building-code compliance review over your plan set, resolving the jurisdiction, the adopted edition, and the local amendments, then returning cited findings by discipline.
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