Oregon, California, Maine among states enacting policies to spur construction of missing middle housing

Although the number of new apartment building units recently reached the highest point in nearly 50 years, construction of duplexes, triplexes, and other buildings of from two to nine units made up just 1% of new housing units built in 2022. A few states have recently enacted new laws to spur more construction of these missing middle housing options that fall between single-family houses and large apartment buildings.

Oregon, California, and Maine have effectively ended single-family zoning, with regulations allowing multifamily housing units to be built.

Lawmakers in Arizona and Rhode Island recently introduced similar legislation. Reform of density zoning requirements often provokes a backlash, but faced with dire housing shortages, lawmakers have pressed ahead with the changes.

More than half of the 368,000 multifamily housing units built in the U.S. in 2022 were in buildings with 50 units or more, and nearly 88% of multiple-unit buildings constructed in 2022 contained 20 units or more, according to US Census Bureau data. In comparison, only about 2,000 duplexes were built.