Zoning is the quiet rulebook behind almost every housing argument in America. It decides how many homes can go on a lot, how tall a building can be, how far it must sit from the sidewalk, and how many parking spaces come with it. For most of the last century, those rules pushed US cities toward one basic product: a detached house on a fairly large lot.
Now that rulebook is being rewritten — in city councils, state legislatures and, increasingly, in courtrooms. Supporters call it the most direct way to bring housing costs down. Opponents say it hands neighborhoods to developers and hopes the market sorts the rest out.
This article walks through what the major reforms actually do, what the evidence shows so far, and how to make a useful argument at your own planning commission hearing — whichever side you land on.
Key takeaway: Zoning reform is not one policy. Legalizing a backyard cottage, shrinking a minimum lot size and allowing six-story apartments near a train station have very different effects, and the evidence for each is different too.
The four reforms you will hear about
1. Ending exclusive single-family zoning
This means allowing duplexes, triplexes or fourplexes on lots where only one house was permitted before. Minneapolis adopted the idea in its 2040 comprehensive plan, and Oregon went statewide with House Bill 2001 in 2019, which requires larger cities to allow duplexes on most residential lots and up to fourplexes in cities above 25,000 people, as the state’s land use agency explains.
2. Legalizing accessory dwelling units (ADUs)
An ADU is a second, smaller home on a lot that already has a house: a backyard cottage, a converted garage, a basement apartment. States have steadily stripped away local barriers — lot size rules, owner-occupancy requirements, extra parking — that made them impossible to build.
3. Shrinking minimum lot sizes
Instead of changing how many units are allowed, this changes how much land each home needs. Houston cut its minimum lot size in the urban core from 5,000 square feet to 1,400–3,500 square feet in 1998 and extended the change citywide in 2013. Austin did something similar in 2024.
4. Removing parking minimums
Parking mandates require a fixed number of off-street spaces per unit regardless of whether residents own cars. Minneapolis eliminated citywide parking mandates in 2021, following earlier reductions downtown and near transit, according to Pew’s review of the city’s reforms.
What happened in the cities that tried it
Minneapolis: the most-studied case
Minneapolis is the example both sides reach for. Pew found that between 2017 and 2022 the city grew its housing stock by 12% while the rest of Minnesota added 4%, and that rents in Minneapolis rose just 1% while rents elsewhere in the state rose 14%.
But the details matter. Of the nearly 21,000 units permitted in that period, 87% were in buildings with 20 or more units and only about 1% were in two-to-four-unit buildings. The headline reform — triplexes on single-family lots — produced very little directly. A 2025 analysis by researchers at the Federal Reserve Bank of Minneapolis counted 87 duplex, triplex and fourplex buildings permitted from 2020 to 2024, adding 225 units, against 11,503 units in larger multifamily buildings.
Those same researchers also pushed back on the simplest version of the success story. They argue that much of the rent slowdown after 2020 came from a drop in demand — vacancy rates in Minneapolis rose above those in comparison cities — rather than from new supply alone. Reasonable people read that study differently: some see proof that upzoning was oversold, others note that abundant apartment construction is exactly what let softer demand show up as lower rents.
Minneapolis also shows how contested these plans are procedurally. Environmental groups sued under the Minnesota Environmental Rights Act, and an injunction blocked the 2040 plan from September 2023 until May 2024, when a judge lifted it. The legislature then exempted comprehensive plans from that kind of environmental review, with individual projects still subject to review.
Houston: small lots, lots of townhouses
Houston has no conventional zoning, but it did have minimum lot sizes — and cutting them changed the city’s housing. Pew’s analysis found at least 34,000 townhouses built between 2007 and 2020, often replacing one older detached home with four larger townhouses on the same land.
The affordability effect was real but modest in scope: those townhouses had a median assessed value of about $340,000 compared with $545,000 for other new single-family homes in Houston. And the change touched only about 0.5% of single-family parcels — a point supporters cite as evidence that fears of wholesale neighborhood replacement were overblown, and that critics cite as evidence that the reform reached a limited slice of the market.
You can see how these debates play out locally on the Houston city page in our directory.
California: ADUs worked, lot splits mostly did not
California is the natural experiment in doing several things at once. Its ADU reforms have been the clearest success: ADUs have gone from a rounding error to a substantial share of housing permits in Bay Area cities.
Senate Bill 9, the 2021 law allowing duplexes and lot splits on single-family parcels, went the other way. The Terner Center at UC Berkeley reviewed 13 jurisdictions after one year and found activity “limited or non-existent.” Los Angeles led with 211 applications for new SB 9 units in 2022, of which 38 were approved. San Diego saw seven. Bakersfield and Santa Maria saw none. Researchers pointed to high fees, restrictive local ordinances, financing barriers and competition from the easier ADU path.
California’s next move is bigger. SB 79, signed in 2025, makes qualifying transit-oriented housing an allowed use near specified transit stops in urban counties, with the state’s housing department noting an effective date of July 1, 2026 and an option for local governments to adopt their own compliant plans.
Montana and Texas: reform from red states
Zoning reform does not map neatly onto party lines. Montana’s 2023 session required cities above 5,000 residents to allow duplexes on residential lots (SB 323), required ADU rules (SB 528) and required cities above 7,000 to allow apartments in commercial zones (SB 245). A group called Montanans Against Irresponsible Densification sued. In March 2025, a district judge upheld those three laws but struck down parts of a separate planning law that limited public hearings, finding the restrictions violated Montanans’ constitutional right to participate.
Texas followed in 2025 with SB 15, which requires large cities to allow smaller single-family lots in certain new developments and limits parking requirements to one space per unit, and SB 840, which allows multifamily and mixed-use projects by right in commercial, office, retail and warehouse zones. Both took effect September 1, 2025, according to a summary from law firm Foley & Lardner.
Austin moved on its own first. In May 2024, the council voted 9-2 to cut the minimum residential lot size from 5,750 square feet — a standard unchanged since 1946 — to 1,800 square feet, KUT reported. Council members also voted to study an equity overlay and delayed implementation in gentrifying areas after residents raised displacement concerns. See what is on the agenda in Austin or Minneapolis.
Arguments for and against
| Arguments for zoning reform | Arguments against |
|---|---|
| More legal capacity to build housing where jobs and transit already are | New capacity does not guarantee new homes; SB 9 showed uptake can be near zero |
| Smaller lots and townhouses deliver lower-priced ownership options, as in Houston | Lower-priced new homes still cost more than the older homes they often replace |
| Ends rules that were used historically to exclude lower-income families and families of color | Rapid change in historically disinvested neighborhoods can accelerate displacement |
| Removing parking mandates cuts construction costs and reuses scarce land | Residents in car-dependent areas face real street parking and access problems |
| ADUs let existing homeowners add income and house family members | Infrastructure — sewers, schools, stormwater — may not be sized for added density |
| State laws create predictable rules across a region | State preemption removes decisions from the local hearings where residents can be heard |
| Broad reform plus apartment construction lines up with slower rent growth in Minneapolis | Researchers disagree on how much of that slowdown was supply versus falling demand |
How to be effective at a planning commission hearing
Planning commissions are where most zoning changes are shaped before a council vote. They are also where general opinions have the least effect and specific, verifiable facts have the most.
- Read the staff report first. It is usually posted several days ahead and states exactly what is being changed, what standards apply and what staff recommends. Quote it.
- Comment in writing as well as in person. Written comments enter the record and are read by commissioners who may miss your testimony.
- Be specific about your block. “The corner floods when it rains hard and there is no storm drain on the north side” is more useful than “this is too much density.”
- Ask for conditions, not just yes or no. Tree preservation, sidewalk requirements, affordability set-asides, construction hours and phased implementation are all negotiable in ways the underlying zoning is not.
- Bring numbers you can source. City permit data, county assessor records and your own photos hold up. Estimates you heard secondhand do not.
Our guide on how to speak at a city council meeting covers the mechanics — sign-up deadlines, time limits and how to structure two minutes of testimony.
Questions to ask at your next public hearing
- How many additional homes does staff estimate this change would actually produce over five and ten years, and what is that estimate based on?
- What fees, utility connection costs and design standards would still apply to a small project under the new rules?
- Has the city analyzed water, sewer and stormwater capacity in the affected areas, and what would upgrades cost?
- What displacement protections — tenant right to return, relocation assistance, phased implementation — are included, and who monitors them?
- Does this change apply citywide, or are some neighborhoods exempt? If some are exempt, why?
- If parking minimums are removed, what is the plan for managing on-street parking, and will residential permit parking change?
- How will the city report results, and will there be a public review after two or three years?
- What did other cities of our size see after adopting a similar rule, and can staff share those numbers?
Key takeaway: The most persuasive testimony usually ends with a request a commissioner can actually act on — an amendment, a condition, a reporting requirement — rather than a demand to approve or reject everything.
What you can do next
- Find out what is actually being proposed. Look up your city’s planning commission and council calendar on our town hall calendar, and check your local officials in the government directory.
- Start or join a debate. Housing arguments go better when both sides have to write down their reasoning. Start a debate on a specific proposal in your city, or read what neighbors are arguing in existing debates.
- Know who votes. Use My District to identify the council member and commissioners who will decide, and write to them before the hearing.
- Organize around a specific ask. If you want a condition added — a tree ordinance, an affordability requirement, a parking study — a citizen initiative or petition is a way to show the size of the constituency behind it.
- Brush up on the vocabulary. Terms like variance, setback, by-right and comprehensive plan come up constantly in these hearings; our glossary defines them.
