The Black Box of Single-Family Zoning Reform

America faces a staggering housing affordability crisis. The consequences of the crisis include reduced economic productivity, suppressed labor mobility, greater social inequity, and increased homelessness. A scholarly consensus blames excessive land-use regulation for these problems and advocates now call for deregulation. Several jurisdictions have recently elected to allow middle housing—small, multi-family developments—in areas previously zoned for single-family detached housing. The results of these reforms, however, have been disappointing. This Article examines why they have fallen short and how to do better. This Article identifies an analytical disconnect between the deregulatory consensus and actual single-family zoning reforms adopted to date. Given this disconnect and the limited success of single-family zoning reforms thus far, it is unclear why such reforms continue to be adopted. Moreover, these reforms cannot achieve their promised ends. Interviews of middle housing builders in reform jurisdictions reveal legal and structural barriers that prevent market participants from responding to the housing crisis with scale and urgency. This Article proposes several regulatory alternatives that offer a greater probability of success in achieving the consensus’s goals: (1) modestly expanding multi-family zones to allow redevelopment and densification of underutilized non-residential properties; (2) providing affordable-housing density bonuses; (3) streamlining land-use procedures and eliminating administrative delay to reduce uncertainty in permitting processes; and (4) reevaluating financing mechanisms for new housing development. Taken together, these policies are necessary complements to single-family zoning reforms for addressing undersupply of market- and below-market-rate housing.