A group of researchers at the Urban Institute came out with a new study on zoning and housing affordability. At governing.com, a headline about the study screamed: “Zoning Changes Have Small Impact on Housing Supply.” The Governing writer’s spin was, of course, “there’s no evidence it [upzoning] makes housing cheaper.” Governing has published numerous articles that criticize pro-supply zoning reform (one of which I critiqued on this blog), so this conclusion seems to fit in with its general point of view.
The most important conclusion (to me) of the study is that it reinforces the commonsense view that lower housing supply leads to higher costs. In particular, the study concludes: “Reforms tightening regulations are associated with increased rents, potentially worsening conditions for low- and moderate-income renters.” (page 4, emphasis mine).
What about upzonings (reforms that allowed more construction)? The study concludes that they “lead to a 0.8 percent increase in housing supply, on average.” (p. 28). How small is 0.8 percent? In fast-growing Harris County, Texas (Houston and its inner ring suburbs), 17 percent of the county’s 1.885 million units have been built since 2010, or about 1.7 percent per year. So 0.8 percent increase would be only five or six months’ worth of new housing in Houston- not a huge amount. Given the miniscule amount of reform the lack of impact on housing prices should hardly be surprising.
In other words, if zoning allows six months’ worth of new housing (compared to the pre-reform status quo), things stop getting worse but don’t really get better. If zoning allows less housing, things get worse.