A surge of homes hitting the market as Baby Boomers downsize is expected to boost housing supply in lower-density areas across the U.S. over the next 15 years, potentially reshaping regional demographics, according to a new report from Zillow. More than a quarter — 27.4% — of the nation’s owner-occupied homes could be listed for sale in the next two decades as Boomers vacate their properties.

The anticipated "silver tsunami" of home sales is likely to inject significant supply into Midwest and Southern markets, where many empty-nest households are concentrated. This shift could redefine housing availability in these regions and create new opportunities for homebuyers. However, the impact on affordability is expected to be uneven. High-cost markets like Seattle, Austin, and Denver — where housing demand is most acute due to employment opportunities — are unlikely to see a meaningful increase in supply from this trend.

Zillow's report highlights that the number of so-called "empty nest" households reached 20.9 million in 2022, up from 20.2 million in 2017. These households, defined as older owners with no children at home and at least two extra bedrooms, are most prevalent in markets like Pittsburgh, Buffalo, and Cleveland. In Pittsburgh, 22% of households fall into this category — the highest share among large metros — followed by Buffalo, Cleveland, and Detroit.