A New York Times article (2019-06-18) analyzed the debate taking place in some states cities about reducing or eliminating single-family detached homes and replacing them with townhomes, duplexes, or other multi-family dwellings. Supporters argue the move is necessary to address affordable housing, racial inequality, and climate change. Critics argue the move could create infrastructure challenges, reduce property values and quality of life, and fundamentally upset the character of certain neighborhoods.
The article indicated that several jurisdictions are considering the issue. Oregon and California are considering legislation that would end exclusive single-family zoning in most of their states. The Minneapolis City Council ended all single-family zoning in the city in December of 2018. According to an analysis conducted by the article’s authors and UrbanFootprint, 75 percent of residential land in many American cities prohibits the construction of any type of home beyond a detached single-family home. The analysis only looked at land zoned exclusively residential and did not consider mixed-use areas.
The closest city to Maryland that was included in the analysis was Washington, DC, which has 36 percent of its residential land zoned for detached single family homes. In the map below, the red areas indicated single-family dwelling zones while the green indicates multi-family dwelling zones (primarily rowhomes).

Single-family zoning “means that everything else is banned,” said Scott Wiener, a California state senator, speaking this spring at the Brookings Institution in Washington. “Apartment buildings — banned. Senior housing — banned. Low-income housing, which is only multi-unit — banned. Student housing — banned.” …
The lesson of Minneapolis, said Salim Furth, an economist at the conservative Mercatus Center, is that a single, sweeping edit to these maps may be politically easier than block-by-block tweaking. …
People elsewhere say their legitimate fears about traffic or the environment have been mischaracterized, caught up in an emotional debate over race and fairness. Martin Henry Kaplan, an architect in Seattle whose neighborhood association sued to block looser regulations on “accessory dwelling units,” recalled as a child that his parents couldn’t buy a house in a neighborhood where Jews weren’t welcome. …
Policies originally conceived in part to be exclusionary, he said, can still be useful toward nonexclusionary ends, like ensuring that neighborhoods don’t have more residents than their sewers can handle, or that families who sink their savings into a home know what to expect around it.
The article also examined how New York, Charlotte, Los Angeles, and some other jurisdictions zone for single-family detached homes and how they are considering the growth challenges they face today.