A growing number of American families are living under one roof across multiple generations, reshaping housing demand nationwide and commanding higher home prices, according to a new report from Realtor.com.

Nearly 4 million owner-occupied homes now house multigenerational families, defined as three or more generations living together. That represents about 4.5% of U.S. households in 2024, up from 4.3% in 2019.

The trend is being driven by high housing costs, child care expenses and a desire for shared living arrangements, particularly in urban areas.

"Multigenerational living is a meaningful force in the housing market," Hannah Jones, a senior economic research analyst at Realtor.com, said in a statement. "Buyers are not being deterred by higher price tags, and in some markets, supply is struggling to keep up."

Homes designed for multigenerational living -- often featuring in-law suites, guest houses or separate entrances -- are offered at a premium. The median list price for such homes in 2025 was $709,000, about 65% higher than the $429,900 median for standard listings nationwide, according to Realtor.com.

Even after accounting for larger sizes, these homes still cost more per square foot, the report found -- $262 per square foot compared with $215 -- reflecting demand for specialized features and their concentration in high-cost markets.

Despite the higher prices, buyer interest remains strong. Multigenerational listings received 13.5% more online views than typical homes and sold in a median of 59 days, roughly the same pace as other properties, Realtor.com said.

California dominates the supply of multigenerational homes, with several of the nation's top markets located in the state.

In San Diego, 22.7% of listings are considered multigenerational -- the second-highest share among major U.S. markets behind Los Angeles. The typical multigenerational home in San Diego is listed for about $1.42 million, roughly 18.8% higher than standard homes in the region, according to the report.

Unlike some parts of the U.S. where these homes are rare and command steep premiums, multigenerational housing is relatively common in California, where high home prices and cultural norms have made shared living more mainstream.

Across the state, price premiums tend to be more moderate. In Los Angeles, multigenerational homes cost just 1.6% more than typical listings, while in the San Francisco area the premium is about 8.4%.

The picture differs sharply in the Midwest and parts of the South, where such homes are scarce. In cities like Detroit and Cleveland, multigenerational listings make up just a small fraction of the inventory but can cost more than double the price of standard homes when they become available.

Those listings also draw significantly more attention from buyers. In Detroit, multigenerational homes receive about 82% more online views than typical listings, while in Cleveland they see nearly 78% more interest.

The typical multigenerational household includes about five people living in a four-bedroom home, with a median household income of $131,000, the report stated. These households reflect the diversity of American families, spanning a wide range of racial and ethnic backgrounds.

Economists say the number of multigenerational households has grown steadily during the past decade, rising from 3.2 million in 2014 to nearly 4 million today, even as the share of total households has remained relatively stable.

The arrangement is expected to remain a significant part of the housing market as affordability challenges persist, giving both buyers and sellers new incentives to consider homes designed for extended family living, according to Realtor.com.