When cities relax zoning, what happens to prices?
Three real-world zoning experiments: Minneapolis eliminated single-family-only zoning in 2018, Oregon legalized duplexes statewide in 2019, and Texas preempted most local building-code restrictions in 2022. We compare permit activity in affected metros against matched controls — the supply response runs roughly 18% to 27% above the counterfactual over five years. Translated to prices, those reforms look like they’ll hold house-price growth down by 0.6 to 1.4 percentage points a year through 2030 in the metros they touch. Useful if you’re underwriting a thesis around policy-driven supply.
1. The three reforms
| Reform | Year | Scope | Headline change |
|---|---|---|---|
| Minneapolis 2040 Plan | 2018 | City | Eliminated single-family-only zoning citywide |
| Oregon HB 2001 | 2019 | Statewide | Duplex-by-right in cities >10k; triplex+ in cities >25k |
| Texas HB 2439 | 2022 | Statewide | Preempted most municipal building-material restrictions |
2. Methodology — diff-in-diff with matched controls
For each reform metro (Minneapolis, Portland, Austin), we built a synthetic-control counterfactual using a weighted combination of matched metros (similar population, income, pre-reform permit trajectory, labor market). Outcome: log-permits per 1k population, by quarter. The estimator is:
log(permits/pop)_{it} = β × Treated_i × Post_t
+ γ × Quarter_t + δ × Metro_i + ε_{it}
where β identifies the reform effect on the treated metro
post-reform, after absorbing quarter and metro fixed effects.3. Results
3.1 Minneapolis — duplex-by-right effect
The estimated +22% permit lift came primarily from 2–4 unit builds. Single-family permits actually fell slightly (-3% vs counterfactual), consistent with substitution toward denser product rather than overall market growth. Multifamily permits (5+ units) were essentially unchanged — the binding constraint for mid-rise construction was elsewhere (parking requirements, not zoning).
3.2 Portland and Oregon HB 2001 — slow burn
Oregon's state-level reform showed the slowest uptake: +5% lift at 24 months, +12% at 36, +18% at 60. The lag reflects the time required for municipalities to update local codes to comply. The rollout is informative for investors pricing in 2024 reforms (Vermont, Minnesota, Washington state) that are following a similar statutory path.
3.3 Austin HB 2439 — material cost channel
The Texas preemption is interesting because it operated through a different channel — build cost — rather than zoning-permitted density. The estimated +27% permit effect reflects lower per-unit cost enabling previously marginal projects. The mechanism is distinct enough that it should not be extrapolated to other "zoning reform" conversations.
4. Price impact
Applying our v0.2 forecast model with reform-informed supply inputs versus the counterfactual, we estimate price impacts:
5. Forward-looking — who's next?
Monitoring state-level legislation, seven additional states have passed or are close to passing material zoning reforms in 2025: Vermont, Washington, Minnesota, Connecticut, Colorado, Maine, and Massachusetts. Our framework forecasts supply elasticities in the +10% to +20% range five years out, with price impacts of -50 to -110bp annualized. For investors, this is a cross-cutting signal: markets in these seven states face materially higher forward-supply risk than our pure-momentum forecasts capture.
References
- [1]Building permits from Census BPS monthly filings, aggregated to MSA-quarter.
- [2]Synthetic control weights computed using the standard Abadie-Gardeazabal method on 8 pre-reform characteristics.
- [3]Minneapolis 2040 Plan: full text at minneapolis2040.com. Oregon HB 2001: Oregon Legislative Information System. Texas HB 2439: capitol.texas.gov.
- [4]Price impact estimated by re-running the v0.2 forecast with permit-series replaced by counterfactual values; difference attributed to reform.