The Builders Already Picked Their Next Boom Towns (And They're Not in Austin Anymore)

In 2019, Travis County, Texas — Austin — issued 9,524 single-family building permits. In 2024, it issued 4,559. A market that everyone in America had heard of, in the boom decade that everyone read about, just got cut in half. Not by a recession. By the builders themselves, voting with capital, deciding they didn't want to build there anymore.

Meanwhile, in 2024, in Harnett County, North Carolina — population 135,000, the kind of place that doesn't headline relocation lists — single-family permits hit 2,219. That's 247% more than five years earlier. Builders quietly piled into a county most readers of "best places to move" articles have never seen on a map.

Permits are the most leading indicator in the housing data stack. They reflect, in real time, what builders think local demand will absorb six to eighteen months from now. They are not predictions and they are not infallible — builders chase, they don't forecast — but they get punished hard when they get it wrong, so they study local markets more carefully than almost anyone else. When their behavior diverges this sharply, it's worth paying attention to.

The 2022-to-2024 redistribution is one of the sharpest in a decade. Famous Sun Belt metros lost permits at double-digit rates. Mid-sized counties most relocators have never heard of doubled their pipelines.

The Pullback: Where Builders Already Left

Three of the most-cited boom towns of the post-pandemic era saw single-family permit issuance fall meaningfully below their pre-pandemic baseline. Not below 2021's mania — below 2019, before anyone was talking about them.

This is the part that surprised us when we ran the numbers. The shorthand for the past decade has been "people are moving to Austin and Nashville and Tampa, prices keep rising, builders can't keep up." That story expired sometime between 2022 and 2024. Builders aren't behind. They've pulled out.

The Boom Town Index's composite score, which weights twenty-three independent features — none of which are permit issuance — agrees. Travis County ranks #981 of 996. Davidson ranks #980. Hillsborough ranks #916. The model didn't know what the builders were doing. It read the same softening from a completely different angle: declining home values, slowing migration, deteriorating affordability. Two independent signals saying the same thing.

The Pivot: Where Builders Went Instead

The capital didn't evaporate. Builders permit somewhere — building is what they do. So the more interesting question is: where did the rigs and the framing crews and the bank loans go?

Six counties saw single-family permits roughly double or more between 2019 and 2024. None are top-ten Sun Belt headliners. Most readers will not recognize the names.

The pattern across this list isn't accidental. These are mostly second-tier metros adjacent to first-tier ones (Harnett spills out of the Raleigh corridor; Knox is what Nashville was a decade ago; East Baton Rouge sits two hours from a New Orleans that's losing people). They have lower home-price baselines — Mobile's median home is $164,600, less than half Austin's. They have less of the pandemic-era supply overshoot to digest. And, in several cases, they have specific economic engines (Permian energy in Midland, university-plus-government employment in East Baton Rouge, manufacturing hubs in Knox and Bonneville) that builders read as durable.

Again, the Boom Town Index agrees from a different direction. Bonneville ranks #329 nationally with a composite score of 66.7. Harnett sits at #356 with 64.0. Midland at #376 with 62.0. The model never saw the permits. It saw wage growth, migration inflows, affordability, and the supply-demand math. The signals converge.

One More Surprise: Mercer County, New Jersey

The most counter-intuitive county on the list isn't in the Sun Belt at all. Mercer County, New Jersey — the Trenton-Princeton corridor — saw single-family permits jump from 181 in 2019 to 827 in 2024. That's a 357% increase in five years, in a Mid-Atlantic state that lost population to net migration every year of the past decade.

What it tells you is that the redistribution isn't just Sun-Belt-to-deeper-Sun-Belt. Some of it is Northeast-stays-Northeast, but flows from supply-constrained primary markets (greater NYC, Philadelphia) into adjacent counties where builders can actually get permits approved. The headline migration data misses this entirely — it sees New Jersey "losing" people and reports a story, but builders inside Mercer are reading a tight, under-supplied market with constrained competition and pricing power.

This is the underused thesis: high-cost regions where builders are finally finding a county that lets them build are some of the most asymmetric supply opportunities in the country. Mercer's median home value is $423,900 and its 12-month home-price change is essentially flat — a market builders think they can supply into without crashing prices.

How to Read Permits When You're Evaluating a Move

If you're considering a relocation, permits aren't the only number to look at, but they belong in the first three. Here's the three-question framework we use:

1. What's the 5-year trend, not the 1-year change?

2022 was a peak year nationally. Comparing any county's 2024 permits to its 2022 number will make almost everywhere look like a bust. The honest comparison is 2024 versus 2019 — the last pre-pandemic year. If 2024 is below 2019, builders have structurally downgraded the market. If 2024 is above 2019 but below 2022, builders are correcting an over-supply but still bullish on the long arc. Those are different signals.

2. Are single-family permits leading or lagging?

Multifamily permits move in big chunks — a single 400-unit apartment tower can dominate a small county's year and revert the next. Single-family permits are smoother and more reflective of local builder conviction about owner-occupier demand. When evaluating a place you'd move to as a household, look at single-family. Mercer County's headline number includes a multifamily push; the single-family number — quadrupling — is what tells you builders see real owner-occupier demand.

3. Does the permit signal agree with at least one other independent signal?

Permits alone are necessary but not sufficient. Triangulate: are wages still growing? Is the home-price-to-income ratio reasonable? Is net migration positive? Where the Boom Town Index is most useful is exactly this — it gives you twenty-three features that have nothing to do with permits, and when the permit data and the composite score point the same direction (as in all twelve counties above), you have higher conviction. Where they disagree, you have a question to investigate.

What Permits Don't Tell You

To be clear about the limits: builders aren't oracles. They got 2021 wrong (over-permitted everywhere). They sometimes pile into a county because one large national homebuilder bought a tract, not because the underlying demand thesis is sound. They can't see beyond their own balance sheets — they can't tell you a county is great to live in, only that it's profitable to build in.

Permit data also lags reality by a few quarters. The 2024 totals reflect builders' demand reads made in 2023, when mortgage rates were peaking and the pullback in famous boom towns was at its sharpest. As of mid-2026, with rates moderating and the worst supply digestion behind some metros, the next round of permits may tell a different story. Always check the most recent monthly issuance against the trailing 12-month average — Census publishes both, free, no subscription.

What permits are very good for: identifying when the consensus narrative about a metro is stale. The story that "Austin and Nashville are still booming" is two years past its expiration date according to the people building the houses. The story that "the next boom towns are big-name Sun Belt destinations" is missing what the data has been saying since 2023. The builders moved on. The relocation-list writers haven't caught up.

Where to Look Next

If you want to dig into the underlying data: each of the twelve counties above has a full Boom Town Index breakdown page with permits history, BTI composite score, scenario forecasts, job growth, home-price trajectory, and similar-metro comparisons. Use those as starting points — not because the score is the final word, but because seeing all twenty-three features in one place makes it harder to fool yourself.

A few related reads:

• 5 Signs a "Fastest-Growing" County Has Already Peaked — companion piece on reading the broader stale-list problem
• Housing P/E Ratio: How to Value Real Estate Like a Stock — the valuation lens that crosses with permits to triangulate
• Fastest-Growing Counties — BoomTownIndex Rankings — the full BTI top-100 by composite score
• Methodology — how the BTI is built and what the 23 features measure

The builders already told you where they think the next decade goes. The rest of the journalism will catch up in eighteen months.