How Many Building Permit Jurisdictions Are There in the US? (Way More Than You Think)

The United States has roughly 20,000 building permit jurisdictions, the city, county, or other government office (formally, the Authority Having Jurisdiction, or AHJ) with the legal power to approve construction and issue permits on a property. The Department of Housing and Urban Development's SOCDS Building Permits Database tracks about 21,000 permit-issuing places, and the Census Bureau's Building Permits Survey (the dataset HUD's is built on) counted 19,945 in its universe.

If you've seen lists claiming there are about 10,000, they're counting half the country.

Every one of those 20,000 entities writes its own rules, adopts building codes on its own schedule, and keeps its records in its own system, which range from modern portals to a filing cabinet behind the counter. This post covers what these jurisdictions are, who they are, where they are, and how to figure out which one governs a given address.

What is an AHJ?

An Authority Having Jurisdiction (AHJ) is the government entity with the legal power to enforce building codes and issue permits for a specific property. When you remodel a kitchen, replace a roof, or build a warehouse, the AHJ is who reviews the plans, issues the permit, and sends the inspector.

The definition is simple. Finding your AHJ is not, because "the government entity" could mean any of dozens of different things depending on where the property sits. It might be the county, if the property sits outside city limits. It might be a township, a borough, a state agency, a tribal council, or the federal government. Occasionally it's two of them at once.

Who actually issues building permits?

Usually a city or county building department, but the full roster is longer and stranger:

And here's the thing: the 20,000 figure counts only the standard civilian jurisdictions in the HUD and Census universe. Federal facilities, military installations, sovereign tribal lands, state university systems, and special authorities (airports, ports, transit districts) are separate from that count entirely. The true number of entities that can issue a building permit in America is comfortably north of 20,000, and nobody (including the federal government) tracks them all. Since 2022, the Census Bureau collects monthly data from only about 8,600 jurisdictions and statistically imputes the rest.

Adding to the confusion, an AHJ doesn't always do its own work. Florida law (§553.791) lets property owners hire licensed private providers to run plan review and inspections, and the local building official is legally required to accept their affidavits. The authority stays public; the verification is outsourced.

Which states have the most permit jurisdictions?

Pennsylvania, and it isn't close. Counted from the Census Bureau's Building Permits Survey place universe (December 2024), Pennsylvania has 2,311 permit-issuing jurisdictions, 72% more than second-place New York:

At the other end: Nevada has 31, Hawaii has 4, and the District of Columbia manages with 1. California, with nearly 40 million people, gets by on 520, fewer than Iowa. (The full 50-state table is at the bottom of this post.)

Why does Pennsylvania have so many? It's not a data glitch, and it's not a mystery. Pennsylvania's Uniform Construction Code lets each of the state's roughly 2,560 municipalities individually choose whether to administer and enforce the code itself, and about 90% opted in. Every one of those boroughs and townships (some with a few hundred residents) is its own permit office. Wisconsin, Minnesota, and New England run on similar town-level government, which is why the upper Midwest and Northeast dominate this table while Sun Belt states centralize at the county.

One more thing about counts like these: they're a snapshot. Jurisdictions annex, incorporate, dissolve, and hand enforcement back and forth constantly, which is why any downloadable "complete list of AHJs" starts is outdated the day it's exported.

Do ZIP codes tell you the permit jurisdiction?

No, and assuming they do is one of the most common (and expensive) mistakes in property data.

ZIP codes were invented by the Postal Service in 1963 to optimize mail routes. They ignore municipal boundaries completely. ZIP 94608 covers both Emeryville and part of Oakland; ZIP 20135 crosses the state line between Virginia and West Virginia. A single suburban ZIP can contain a city, a village, and an unincorporated county pocket, each with its own permit office.

The failure mode is sneaky: a property sits in an unincorporated pocket, someone checks the surrounding city's permit database, finds nothing, and concludes the property's addition was never permitted. It was, by the county. A false negative like that can misprice an insurance policy or derail a closing, and the data was right there the whole time, one jurisdiction over.

California's Coachella Valley takes this to its logical extreme. In 1876, the federal government granted the Southern Pacific Railroad alternating one-mile-square sections of land in a checkerboard pattern; the sections that weren't handed to the railroad were later set aside as the Agua Caliente Indian Reservation. That 150-year-old survey grid still governs permitting today across Palm Springs, Cathedral City, Rancho Mirage, and Palm Desert, which means the permit jurisdiction can flip block by block, sometimes lot by lot, as you drive down an ordinary street. Your house and your neighbor's, on the same block, same ZIP code, same street address format, same everything a database would normally use to group them: one calls the city, the other calls the tribe, and nothing about the property itself tells you which.

Why does any of this matter?

Because a lot of money rides on knowing which of the 20,000 rulebooks applies to a property:

• Insurance. Model codes like the IBC have no legal force until an AHJ adopts them, and adoption cycles vary by decades between neighboring jurisdictions. Insurers pricing ordinance and law coverage without knowing the local code are setting rates with a dartboard. A very expensive dartboard.
• Real estate and lending. Fannie Mae's appraisal guidelines require appraisers to flag unpermitted additions, which generally can't count toward square footage. In high-value markets, one unpermitted garage conversion can knock six figures off an appraisal.
• Construction. Permit timelines for the same project range from same-day to the better part of a year depending on the AHJ. After the Los Angeles fires destroyed 11,200 structures, months into recovery only four rebuilding permits had been issued.

We've written more about what permit records reveal for property risk and insurance claims.

How do you find the AHJ for an address?

The traditional method: check whether the address is inside city limits (the county GIS map usually knows, if you can find it), call the city, get told it's actually the county's problem, call the county, and hope the property isn't in an ETJ, a special district, or a municipality that outsources enforcement to a neighbor. It works, one address at a time, if you're patient.

That's fine for a homeowner. It does not work if you're underwriting a thousand policies, running due diligence on a portfolio, or routing permit applications across state lines, which is why we built the jurisdiction resolution layer into the Builty API. Give it an address, and it returns the governing jurisdiction and the standardized permit history behind it, kept current as boundaries shift. The 20,000 bosses aren't going to unify their systems, so we did it for them.

Permit jurisdictions by state (full table)

Counted from the Census Bureau Building Permits Survey place universe. State totals reflect standard civilian permit-issuing places; federal, tribal, and special-purpose authorities are additional.

For what a permit record actually contains and why it matters for risk, start with What Is a Building Permit, and What Can It Reveal About Risk? For the insurance angle, see Property Claims Blind Spot: Building Permits.