Rents are regulated by the city government so that none of the residents pay any more than 20 to 25 percent of their household income for housing, compared to the corresponding 30 percent benchmark in the U.S. A unique feature of Vienna’s social housing program, Lindstrom noted, is that the city’s income restrictions for subsidized units only apply when families first move in. Residents are never required to move out, even if household income levels increase in the following years.
This arrangement results in a substantial number of moderate-income residents living in subsidized housing, and this mixing together of residents with different income levels helps with social integration. Since the city has a large stock of affordable housing, these middle-income residents typically do not crowd out lower-income residents.3 Because the city continues to add new units that are subsidized, about 5,000 annually, and available to lower income residents, housing developments do not devolve into middle-class enclaves nor do they become stigmatized concentrations of poverty.
