Restrictive zoning limits housing supply, which (according to the law of supply and demand) increases housing costs. But some commentators argue that more permissive zoning would actually increase housing costs by increasing land costs. This article points out that if the latter claim was true, land costs would have risen in places that allowed lots of new housing and fallen in more restrictive regions such as San Francisco. In fact, land costs increased in both types of metro areas. More importantly, overall housing costs increased more rapidly in more restrictive metros.