Sustainable Communities Act of 2019 This bill requires the Department of Housing and Urban Development (HUD), in coordination with the Department of Transportation, to create a Sustainable Communities Initiative to improve regional planning efforts that integrate housing and transportation decisions and improve land use and zoning. As part of this initiative, HUD must administer two grant programs. Specifically, HUD must provide Regional Integrated Planning grants for regional, multi-jurisdictional organizations and consortia in metropolitan areas to support improvements in, and coordination of, metropolitan-wide housing, transportation, energy, and land-use planning activities; and Community Challenge Planning grants for units of local government to foster reform and reduce barriers, including through the reform of existing building codes and zoning ordinances, to achieve affordable, economically vital, and sustainable communities and discourage inefficient land-use patterns.