SAN FRANCISCO—The Bay Area is at risk of losing Millennials in the years ahead, as high housing costs are making them increasingly unsure about the ability to move into homes in the livable neighborhoods they desire. In addition, one-third of the respondents from the South Bay, which has the largest number of Millennials, say they are not satisfied with local housing options. The low expectations of Millennials in the Bay Area are in stark contrast to Millennials in the country as a whole, where 52% said they anticipate being able to purchase or rent their desired housing in five years.

The report, which was released at the ULI Fall Meeting finds that 74% of Millennials living in the Bay Area are considering moving during the next five years, away from the area rather than within it. Just 24% are very confident that they will be able to own or rent their desired home in five years, a dramatically lower percentage than Gen Xers, 38% of who voiced strong confidence in their ability to move up; or Baby Boomers, at 49%.

Another possible indicator of housing affordability challenges for the Bay Area's youngest adults point to 34% of Millennials who currently live in apartments—compared to 21 percent of Gen Xers and 11% of Baby Boomers. An equal percentage of Millennials expect to be living in apartments in the future, compared to just 11% of Gen Xers and 8% of Baby Boomers.

The report also shows that Millennials in the Greater Bay Area place the highest priority on health-related attributes including air and water quality, access to public transportation and bike lanes. Yet, they are the least likely of the generations to have easy access to safe places for outdoor physical activity and active transportation systems.

The findings should serve as a wake-up call—not just for the region's technology industry with its Millennial-heavy employment base—but for how San Francisco grows for the future, said ULI Global chief executive officer Patrick L. Phillips.

"Millennials make up the largest, most diverse generation in our history, and they will have an enormous impact on the success of our cities. San Francisco needs to consider how the declining housing affordability is affecting the high quality of life it is seeking to provide for all residents, including this powerful group," he said. "This means placing a strong emphasis on providing housing for a mix of incomes and generations, and by investing in development patterns to further reduce automobile dependence and promote health and wellness."

Bay Area in 2015 is based on a survey of 701 adults in the Greater San Francisco Bay Area that was conducted during February 2015 as a companion to a national survey conducted for ULI's America in 2015 report, which was released last spring. Survey responses are categorized by generation—Millennials, Generation X, Baby Boomers, War Babies and the Silent Generation—as well as by ethnicity, income and location (comprised of the North Bay, the five-county Bay Area and South Bay).