How to Find the Local Design Criteria for a Jurisdiction

Why this matters

The design criteria table is the one page of local code that changes the most jobs, and it is surprisingly hard to find. It is rarely on the permit application, often buried in an ordinance, sometimes printed on a building department handout that is two code cycles out of date, and occasionally only in the head of the plans examiner. A shop that expands into a new town or takes a job across a county line needs a repeatable way to get the real values, from the right authority, for the right edition, and to write them down once. What each cell of the table means is covered in The Local Design Criteria Table; this is how to get it filled in.

The steps

1. Confirm which jurisdiction actually governs the address. Look the parcel up in the county's online parcel or GIS viewer, or on the assessor's record, and find the jurisdiction or tax district, not the mailing city. A house with a city's name in its address can sit in an unincorporated area governed by the county, or in a township or village with its own building department. In some states a statewide code applies with limited room for local change, and in others the county or city amends heavily. Why first: every later step depends on it. What breaks if skipped: you read the right table for the wrong authority, and nothing in that table will look wrong.

2. Find the edition in force and its effective date. The building department's page usually lists "adopted codes," and a state building code agency publishes the statewide edition where one applies. Write down the edition year and the date it took effect. In many jurisdictions the code in effect when the permit application is filed governs that permit, so a job applied for just before a new adoption may be under the old edition; ask the department how it handles that transition rather than assuming. Why it matters: the model code is republished every three years, but each jurisdiction adopts on its own schedule, and some skip a cycle. What breaks: a table from an edition the jurisdiction never adopted, or one it has since replaced.

3. Go to the adopting ordinance and its local amendments. The legal text is the jurisdiction's code of ordinances, usually published online, in the chapter on buildings or construction. Search it for "R301.2" or "design criteria." The filled-in table is commonly printed in the adopting ordinance itself, as an amendment reading something like "Table R301.2 is completed as follows," often alongside other amendments that matter just as much (a local frost depth, an added strapping rule, a deleted exception). Why the ordinance and not a handout: the ordinance is what an inspector enforces. What breaks: relying on a summary that has drifted from the law.

4. Get the department's handout, and cross-check it. Many building departments publish a one-page design criteria or "local requirements" sheet. It is convenient and often includes items the table does not, such as the required plan sheets, local inspection stops and contact names. Compare every value on it against the ordinance. Where they disagree, the disagreement is a finding, not a typo to correct quietly. What breaks if you skip the cross-check: handouts are updated less often than ordinances, and a stale one is the most common source of a wrong frost depth or snow load.

5. Mark the cells that depend on the address, not the jurisdiction. Some cells are not one value for the whole area. Flood hazards point to a flood map panel that varies street by street. Snow load in mountain areas can vary with elevation or defer to a local study. Wind cells can flag topographic effects or a special wind region on exposed sites, and windborne debris zones follow a mapped boundary. Where a cell says "see map," "per local study" or "site specific," the table has handed the question back to you for each address. What breaks: a county-wide number applied to a ridge-top or a floodplain lot where it does not hold.

6. When it is not online, ask the right person the right question, in writing. Call or email the building department and ask for the plans examiner or the building official, not the permit counter. Ask four things: which code edition and amendments are in force, whether there is a completed design criteria table you can have a copy of, which cells vary by address, and who to ask if a value is unclear. Ask for the answer by email. A verbal answer at the counter is useful for the day; a written one is what you can rely on when an inspector reads the table differently six months later. What breaks: a phone answer from whoever picked up, with no name, date or source attached.

7. Write it down once, with its provenance. Record every value, where it came from, the edition and effective date, the date you retrieved it, and what will make you check again. Keep it in the jurisdiction profile the shop maintains, as described in How to Build a Jurisdiction Profile. The record is only as good as its source line. What breaks: a table copied into a job folder without a date or edition, which nobody will think to re-check when the jurisdiction adopts the next code.

Worked example: a new township, a disagreeing handout

A roofing and deck company takes its first job in a community it has not worked in. The mailing address names a nearby city.

Step 1. The county parcel viewer shows the parcel outside city limits, in an unincorporated part of the county. The city's design criteria are irrelevant. The county building department governs.

Step 2. The county's website lists the 2021 IRC with local amendments, effective on a stated date about eighteen months earlier. The job's permit will be filed this month, so the 2021 edition applies.

Step 3. The county's code of ordinances contains the adopting ordinance, with the completed table as an amendment.

Step 4. The department's downloadable "residential requirements" sheet lists the frost line depth as 36 inches. The ordinance lists 42 inches. The sheet carries no date, and it references the 2015 edition in its header.

Step 6, applied to the disagreement. The office manager emails the building official, quoting both values and asking which governs. The reply, two days later, confirms 42 inches under the current ordinance and says the handout is being revised. The email goes in the file.

Step 5. The flood hazards cell gives dates, not a zone, so the company checks the address on the current flood map separately. The snow and wind cells carry no site-specific notes for this part of the county.

Step 7. The office manager fills in the record below.

JURISDICTION DESIGN CRITERIA RECORD
Authority:  County bldg dept (unincorporated)
Code:       2021 IRC with county amendments
Effective:  per adopting ordinance date
Source:     county code of ordinances, bldg chapter
Retrieved:  this month; confirmed by bldg official
            by email (on file)

Ground snow load ........... 20 psf
Wind speed ................. 115 mph (ultimate)
Topographic effects ........ no
Special wind region ........ no
Windborne debris zone ...... no
Seismic design category .... B
Weathering ................. severe
Frost line depth ........... 42 in
  (county handout says 36 in: outdated, per
   bldg official email; ordinance governs)
Termite .................... moderate to heavy
Winter design temp ......... 1 F
Ice barrier required ....... yes
Flood hazards .............. NFIP entry 1979;
                             FIRM dated 2012
Air freezing index ......... 1,500
Mean annual temp ........... 50 F

Address-dependent: flood (check map per job)
Recheck: on county adoption of next edition

What the record changes on this job. The deck footings go to at least 42 inches, not 36. Had the crew followed the handout, every footing would have been 6 inches short of the frost depth the inspector enforces, which on a deck with eight footings is eight holes to re-dig after a failed footing inspection, or eight footings that heave if the inspection missed it. The reroof gets ice barrier at the eaves because the cell reads yes. Seismic category B triggers no water heater strapping under the IRC, which matters to the plumbing side of the shop the next time it works here.

What would have changed the answer. If the parcel had been inside city limits, steps 2 through 7 run again against the city's ordinance, which may carry a different edition and different amendments. If the building official had not replied, the conservative move on a frost depth is to build to the deeper of the two values and note why, because a deeper footing passes an inspection written to the shallower one while the reverse fails. That shortcut does not work for every cell: a higher snow or wind number can change a product selection or a fastening schedule in ways that are not simply "more," so those get an answer before the job proceeds.

Checking the record is still right

Before each new job in that jurisdiction, read the record's "Code" and "Recheck" lines. If the jurisdiction has adopted a newer edition since the retrieval date, the record is stale in full, not just in the cell you happen to need; run steps 2 through 7 again. And when an inspector cites a value that differs from the record, treat that the way step 4 treats a disagreeing handout: get the source in writing and update the record, so the next quote starts from what the inspector enforces.

References

• International Residential Code, Section R301.2 climatic and geographic design criteria, in the edition your jurisdiction has adopted
• Your jurisdiction's code of ordinances and adopting ordinance for the building code
• Your state building code agency, where a statewide code applies
• See related: The Local Design Criteria Table
• See related: How to Build a Jurisdiction Profile