Residents of Sonoma and Napa counties continue to move out of California at rates that are hampering the region’s population rebound, part of a statewide exodus that has slowed since the end of the pandemic but remains driven by California’s high cost of living, according to new research from the University of California.
Though the out-of-state exodus has declined in recent years, the California Policy Lab, a UC research institute, found that California’s growing unaffordability continues to push local residents to states where they can more easily find housing.
Sonoma and Napa counties continue to see a net loss of residents to other states, following a statewide pattern over the past decade, the institute found.
Between 2016 and 2025, Sonoma County saw a 12,100-person loss in net migration, meaning more people moved out than moved in. Napa County saw a net migration loss of 6,900 residents, according to data from the report. The figures are a component of population change that exclude gains from births and loss from deaths, the other main factors.
“The falling exits in Sonoma and Napa align with what we’re seeing statewide,” said Brett Fischer, a researcher for the California Policy Lab.
Sonoma County’s population stood at 486,444 in 2025, a 3.4% drop from 2016. In Napa County, it was 132,949, down 5.6% from 10 years ago, according to census data.
Ethan Brown, executive director of Sonoma County’s Economic Development Collaborative, said the analysis is closely aligned with what the county has found in its own assessments during a similar period of time.
“I’m not surprised by what we see here,” Brown said in an interview. “I think it has been slowing down here, which could be reflective of local efforts to make the area more affordable.”
The biggest factor driving the slowdown in California population growth over the past 25 years, the study found, is net migration loss — the number of people moving in from other states has increasingly lagged behind those leaving California. The statewide birth rate has also declined during that time, from more than 500,000 births in 2008 to around 420,000 in 2021, according to the Department of Finance data the authors cited. Sonoma County births dropped from 4,964 in 2016 to 4,526 in 2021.
Leading up to the COVID-19 pandemic, exits increased as entrances stayed flat, and around 15% more people left California each quarter than arrived. And while the gap between exits and entrances has shrunk considerably since the pandemic, it has not disappeared. In 2025, nearly 150,000 more people left the state than arrived.
Generally, the average Californian relocated to a neighborhood where monthly housing costs are $672 lower than in the community they left, the report found. Renters who moved typically found new rents at about 30% (or about $631) lower in their new neighborhood. For homeowners, the median home in their new neighborhood costs almost $396,000 (or 48%) less than the median home in their prior neighborhood.
In one of the more interesting dynamics revealed by the report, many of those leaving faced a financial brink.
Researchers found that the average household leaving the state was relatively worse off than their immediate neighbors. Compared to their neighbors, people leaving the state had credit scores that were 17 points lower; twice as much student debt; and were more likely to have their credit cards maxed out.
Moving out of state also helped many of those who exited gain access to the housing market. Homeownership was more common for movers — seven years after leaving California, they were 48% more likely to be a homeowner than those who stayed in the state. By contrast, those who moved to California were only 27% more likely to be homeowners seven years after arriving than they were before they came to California.
“All these signals are consistent with the idea that exiters desire a quality of life that they cannot achieve in their old neighborhood,” the report states.
The institute’s study didn’t breakdown specific county-level migration patterns to see where local residents are moving to or coming from. However, since the 2017 North Bay fires, local residents have moved in droves to states including Texas, Arizona and Oregon.
Still, the largest share of Californians who move aren’t exiting the state.
About three in five stayed within their original county, and since 2016, more than half have moved 10 miles or less. Even after accounting for long-distance moves, the typical move has shortened. After the pandemic, the average distance was 358 miles — 14% less than the pre-pandemic average of 416 miles.
At the same time, more affluent movers tend to relocate further away. During the pandemic, the average mover from the highest-income California neighborhoods relocated 449 miles away — two and a half times as far as the average mover from the lowest-income neighborhoods.
Jack Kampmann, special projects coordinator for Sonoma County’s Economic Development Collaborative, said population data used by the county is slightly different than what was used in the institute’s report. The county uses U.S. Census Bureau data, which tracks everyone, including children.
Kampmann said the county counted a loss of 12,448 residents between 2016–2025 period, compared to the research institute’s figure of 12,100.
Fischer, the report’s co-author, said the difference is likely due to the institute’s use of credit card records in its analysis.
“Our data only include adults with credit records,” Fischer said. “We think about 90% of California adults have credit records, so we probably undercount adult movers by about 10%.”
Tell Us: Have you left Sonoma or Napa counties?
Are you among those who left Sonoma County or Napa County to a state where you have purchased a home, or where your monthly rent is substantially less? We’d like to learn more about your experience for a future story about what’s driving people out of Wine Country.
Send your responses to Staff Writer Martin Espinoza at martin.espinoza@pressdemocrat.
Brown said he thinks it’s difficult to draw conclusions about exactly why people left Sonoma County during the past decade, given that multiple fires, floods and a pandemic taking place during that time.
A breakdown by year of the institute’s exit and entrance data for Sonoma County shows that the largest spike in population loss took place during 2018 and 2021, following the 2017 firestorm and the onset of the pandemic.
For these reasons, Brown said “I would urge caution when looking at a statewide analysis without considering the regional context.
“What’s maybe not there is what we’re seeing in certain regions of California. It was a time when people were losing their homes, and that goes far beyond affordability,” Brown added. “We know we lost 5% of our housing stock in the 2017 fires and later (in) subsequent fires. A lot of that has been rebuilt, but some people didn’t have the ability to rebuild here, and they moved on.”
You can reach Staff Writer Staff Writer Natalie Hanson at 619-665-5887 or natalie.hanson@pressdemocrat.com and Staff Writer Martin Espinoza at 707-521-5213 or martin.espinoza@pressdemocrat.com.