As cities across the country grapple with soaring housing costs, the need for zoning reform is more pressing than ever. Cities are in desperate need of more housing, but exclusionary zoning practices often thwart housing growth. Indeed, a growing body of evidence has identified how exclusionary zoning places artificial constraints on supply, exacerbates residential racial segregation, and contributes to rising housing costs. In response, policymakers have called for zoning reforms that would allow more small homes to be built in expensive markets, which often prohibit non-single-family detached homes. President Biden’s infrastructure plan, which supports awarding grants and tax credits to municipalities that reform their zoning codes to allow multifamily developments in neighborhoods restricted to single-family homes, offers substantial promise to dismantle exclusionary zoning.

These exclusionary zoning practices are rooted in a deeply racist history. Since the early twentieth century, municipalities have wielded local discretion in the land use process to enact a host of exclusionary zoning restrictions. Exclusionary zoning regulations, such as zoning ordinances mandating minimum lot sizes, restricted multifamily development and prevented often working-class, minority households from moving into predominantly white communities. We now know that these effects are durable; previous research has found that restrictive land use regulations enacted earlier in the twentieth century help explain metropolitan segregation patterns over time.

In response, planners and policymakers across the country have renewed calls for cities to reform their zoning codes to allow for denser development, such as allowing duplexes or triplexes in single-family neighborhoods. For example, in 2018, Minneapolis became the first major American city to eliminate single-family zoning. Other cities, such as New York and Seattle, have turned to upzoning policies. Upzonings, which increase allowable densities often by relaxing the zoning code’s height and bulk requirements or increasing floor area ratios, aim to encourage denser development, increase housing supplies, and thus improve housing affordability.

Read the full article about upzoning by Jenna Davis at Brookings.