Dwelling on it: ADUs advance on the coasts and inland

dgbeig housing construction on top of piles of money bills

ADU proliferation faces a fierce and long-entrenched opponent: zoning.

Comedian George Carlin believed that the word “bipartisan” means a “larger-than-usual deception is being carried out.” But the comedian’s legendary cynicism might dissolve, at least a bit, if confronted by the across-the aisle progress underway with a key affordable-housing tool.

Neighbor Blog’s Grant Ongstad defines an accessory dwelling unit (ADU) as “a separate living space that exists on the same property as a primary residence” which “can be attached to an existing structure or detached from the main property.” The domiciles go by many monikers, including casita, granny flat and carriage house. The website AccessoryDwellings.org lists more than 30 names.

An ADU certainly isn’t for everyone, but the demographic data are clear: There’s plenty of demand. In 2023, the Census Bureau revealed that over “a quarter (27.6%) of all U.S. occupied households were one-person households in 2020, up from just 7.7% in 1940.” A U-turn isn’t likely anytime soon. It’s difficult to shack up when you don’t have a significant other, and dating is mired in the doldrums. In January, the Survey Center on American Life coined the phrase “romantic recession.” The marriage rate, flat-lining for a decade, remains at a historical low. Hans-Peter Kohler, a University of Pennsylvania sociologist, sees no “indication of a reversal of the trend towards lower or declining U.S. fertility.”

Yet ADU proliferation faces a fierce and long-entrenched opponent: zoning. In an April essay for the Lincoln Institute of Land Policy, Lynn Richards noted that after World War II, “most housing in America” was “built to support a nuclear family structure: two parents living with their children.” Regulations reinforced the dominant pattern of spacious homes on ample lots in the suburbs. Supercharged by NIMBYism (Not In My Back Yard), change, at all levels of government, hasn’t been easy.

In 2025, despite the undeniable cultural metamorphoses, ADU-friendliness exists on a wide spectrum, with some states known for limited government (e.g., Wyoming, Oklahoma, Kentucky) disappointingly hostile, and some freedom-tramplers (e.g., Oregon, New Mexico, Connecticut) surprisingly supportive. Nowhere is such odd dichotomy stronger than in California, where runaway housing costs have induced a deregulatory revolution.

Per the Mercatus Center, back in 1982 the Golden State enacted a “law that gave homeowners … a weak right to build an ADU.” Broader reforms had to wait until this century, but in the past decade legislative relief has been significant. And the results are undeniable. According to Seal Beach general contractor Cameron Meredith, “ADUs now represent 19% of all housing units produced in California.”

Santa Barbara’s housing is so pricey the local school district has “plans to build around 330 homes for our workforce.” In May, the city launched the far-more-preferable “Preapproved ADU Program: a faster, more affordable way to build detached ADUs,” in part to give “homeowners confidence to invest.” Also last month, Pasadena authorized a “significant reduction in permitting and plan check fees for Accessory Dwelling Units … on single-family sites,” with additional “fee reductions, which require an ordinance … expected to go into effect in July.”

To the north, the Sierra Sun recently reported that the nonprofit Tahoe Housing Hub’s ADU Accelerator Program, which “previously offered free technical guidance and advice to homeowners,” has “been expanded to also cover all or some of the cost of additional services like site surveys, engineering and architectural consultations, legal fees, land planning services and more.”

Three thousand miles away, ADUs are taking hold in the Northeast. Last year, Massachusetts signed off on a sweeping housing-reform statute that establishes a right to build ADUs smaller than 900 square feet “in single-family zoning districts in all communities.” Regulations have been finalized, and local implementation is underway throughout the Bay State, from Marblehead (a suburb of Boston) to Southwick (a suburb of Springfield). Declaring ADUs a “partial but important solution,” in December Palisades Park, New Jersey—immediately across the Hudson River from the Big Apple—permitted the option for both one- and two-family houses. Completing a process begun in 2019, Ithaca, New York, has authorized ADUs, even for non-owner-occupied homes.

And in the Heartland? Iowa is a perennial star in housing-affordability rankings. But like other states in Flyover Country, it’s getting ahead of a potential problem. A few weeks ago, Gov. Kim Reynolds, a Republican, signed Senate File 592, a bill State Rep. Adam Zabner, D-Iowa City, hailed as “a wonderful step in creating new opportunities for Iowans, in creating new housing and finding a place to live.” The legislation curtails the “limitations or restrictions” local governments may impose on ADUs.

Last fall, Montana’s Supreme Court scrapped a NIMBY-driven legal challenge to housing reforms in Big Sky Country. In a 5-0 decision, justices agreed that neighbors’ “generalized fears and supposition” about the growth of ADUs and duplexes weren’t sufficient to overturn lawmakers’ policy prescriptions for cheaper housing. Treading lightly, officials in the Sooner State’s capital are crafting an ordinance to “allow accessory dwellings in backyards in limited parts of Oklahoma City and only under certain conditions.” The local association of Realtors backs the measure, citing “Edmond, Norman and Tulsa” as cities that “have embraced ADU policies, allowing homeowners greater flexibility to create more housing options. The benefits of increasing the housing supply clearly outweigh the risks.”

Despite mounting setbacks, the enemies of ADUs aren’t about to buckle. This session, the taxpayer-funded Texas Municipal League opposed a bill to limit municipal control of ADUs in the Lone Star State because it might have harmed “the very communities it seeks to serve by eliminating several important planning considerations necessary to protect public health and safety.” And it’s worth noting that many big government policy entrepreneurs see the increasingly popular housing reform as a way to meddle in the market, via subsidies and tax “incentives.” But as long as having a place of your own in America remains prohibitively expensive for many—and living alone becomes more commonplace—ADU deregulation makes sense, no matter where it’s adopted.

Dowd Muska is a researcher and writer who studies public policy from the limited-government perspective. A veteran of several think tanks, he writes a column and publishes other content at No Dowd About It.

Nothing contained in this blog is to be construed as necessarily reflecting the views of the Pacific Research Institute or as an attempt to thwart or aid the passage of any legislation.

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