Every city that legalized the multiplex, and what actually happened

On the evidence, Auckland, New Zealand. Its 2016 upzoning is the most-studied on Earth and peer-reviewed work found it added about 21,808 homes in five years and lowered 3-bedroom rents by roughly 20–35%. Portland and Japan are the other standouts for measurable, durable results, because both give small buildings enough floor area to actually pencil out.

Yes. Calgary repealed its 2024 citywide rezoning in April 2026, and Gainesville, Florida reversed its reform within about six months in 2023. New Zealand made its national mandate optional for Auckland and Christchurch after the 2023 election. Arlington, Virginia was voided in court, then reinstated on appeal, and is in effect in 2026 while under Supreme Court review.

Not by itself. California SB 9 was modeled to make about 700,000 homes feasible but produced only 53 approved units across 13 cities in its first year, and Sacramento built zero mid-size projects in its first 18 months. Legalization is necessary but not sufficient. Financing, construction cost, and floor-area limits decide what actually gets built.

BC's Bill 44 is among the most ambitious mandates anywhere: a province forcing 3 to 6 homes onto single-family lots, scaled by transit, with no city opt-out. It most resembles Washington's HB 1110 and New Zealand's MDRS. The open question is durability and real uptake, which is exactly what these other cities reveal.

Missing middle housing means the range of home types between a single detached house and a large apartment tower: duplexes, triplexes, fourplexes, townhouses, and small courtyard or cottage clusters. These were common in older neighbourhoods but were made illegal in much of North America by single-family-only zoning. The reforms on this hub are mostly about making that middle range legal again.

Minneapolis was the first big US city (2020), followed by Oregon and California statewide, Washington State, Berkeley, Edmonton, and others. British Columbia did it province-wide through Bill 44. "Ending single-family-only zoning" does not ban houses. It means those same lots may also hold two or more homes.

Because a unit limit on a map does not build anything on its own. Minneapolis legalized triplexes citywide but only about 1% of its new homes came from 2-to-4-unit buildings, because the building-size rules were too tight. The reforms that actually produced middle housing (Portland, Auckland) gave smaller buildings enough floor area, removed parking mandates, and let owners sell the homes separately.

Auckland stands out for measured results: roughly 21,808 extra homes in five years from its 2016 upzoning. Japan, through its permissive national zoning, lets Tokyo build well over 100,000 homes a year, more than some entire countries. Houston, with no zoning at all, produced tens of thousands of townhomes by cutting its minimum lot size.

The best evidence says yes, where enough gets built. Auckland saw 3-bedroom rents fall sharply against a comparison group, and Minneapolis held rent growth to about 1% while the rest of Minnesota rose 14%. New middle-housing homes also sell for far less than new single houses, often $250,000 to $300,000 less in Oregon and Portland. Where little gets built, the price effect is small.

It varies widely. Most allow 2 to 4 homes on a lot, often more near transit. Some go further: British Columbia allows up to 6 near frequent transit, Seattle up to 6 (and more with bonuses), and Edmonton up to 8. California SB 9 allows up to 4 through a lot split. The number on paper matters far less than the floor area and financing behind it.

Most North American and Australasian reforms change local zoning to allow more homes. Japan is the outlier: it sets zoning nationally through 12 permissive, nested use zones, so most residential land allows small apartments and shops by right. That centralized, permissive system is a big reason Tokyo builds so much housing and has kept it relatively affordable.

Two things. First, the legal right to build more homes now exists in far more places than most owners realize, so check your own lot. Second, do not assume the maximum. On most lots the real limit is floor area, land cost, and financing, not the headline unit count, so the honest number is often lower than the law allows. Run the specific lot before you commit.