While housing costs for some of the Bay Area’s poorest residents skyrocketed far beyond the income they gained over the past decade, the region’s wealthiest households saw their housing costs actually drop as their incomes swelled.

Those vastly different experiences have helped make the San Jose and San Francisco metropolitan areas among the most economically unequal regions in the country, according to a new study from Apartment List that looked at incomes and housing costs from 2008 to 2017.

In the San Francisco metro area, which includes Redwood City, Oakland and Walnut Creek, the poorest 25 percent of households saw their incomes go up an average of 8 percent while their housing costs increased by an average of 24 percent between 2008 and 2017, the study found. Meanwhile, the wealthiest 5 percent of San Francisco metro households saw their incomes increase 21 percent and their housing costs decline 3 percent.

That trend was not as pronounced in the San Jose area, which includes Palo Alto and Milpitas, where the poorest 25 percent had on average 12 percent higher incomes and 13 percent higher housing costs. The top 5 percent saw their housing costs decline 1 percent while incomes grew by 22 percent.

The plodding income gains for those at the bottom of the economic ladder occurred despite years of declining unemployment and a booming Bay Area economy, said Igor Popov, chief economist at Apartment List.

“This should be the time where everyone is celebrating and feeling good about themselves,” he said. “But so many people in the economy are saying, ‘Wait, these are the good times and a recession is coming? This doesn’t feel like the good times.'”

The trend lines for income and housing costs diverged most sharply for those at the very bottom of the income ladder. The poorest 5 percent of San Francisco metro residents saw their income drop 2 percent as their housing costs grew by 34 percent, the study found.

What surprised Popov was that among the wealthy, it’s not simply that their housing costs are declining as a share of their higher income. The study showed their actual costs dropped, too.

That’s in part thanks to low interest rates, which have allowed wealthy residents and those who already own their homes to refinance their mortgages and bring down their housing costs, Popov said.

But at the other end of the economic spectrum, people are increasingly competing for — and pushing up the sales price of — older homes that used to be an affordable refuge for working-class families.

Residents and affordable housing advocates worry that the one-two punch of smaller income gains and higher housing costs is eroding long-standing communities by displacing working-class residents.

Read The Price We Pay: How Housing Costs are Transforming the Bay Area

Betty Gabaldon, 43, who moved to Concord about 20 years ago to be closer to her mother, saw her housing costs double in the past eight years. She said she works about 66 hours a week at a full-time job in merchandising plus a second, part-time bookkeeping gig.

When she first moved into her two-bedroom apartment, she and her mother paid about $1,000. But last year, she said she received a no-cause eviction notice, which is allowed in Concord. She moved to a new two-bedroom, where the rent is about $2,000 a month.

Gabaldon, who has advocated for renter protections and previously served on the Concord rent review panel, said most landlords asked for proof that her income was three times the monthly rent. Although both she and her mother work, that was a nearly impossible barrier.

“They want you to make at least $6,000 to be able to qualify to rent an apartment,” she noted.

The stress of the constant rejections started to get to her 10-year-old daughter, who worried about changing schools and leaving friends she’s known since kindergarten. “‘What are we going to do now, mom?'” Gabaldon remembers her daughter asking. “‘Are we going to live on the streets? Are we going to be homeless?'”

Eventually, Gabaldon was approved for a new apartment. She had to leave Concord but still lives nearby.

The difference in income growth among the poor and the wealthy have made the San Francisco and San Jose regions the fifth and seventh most economically unequal in the country, the Apartment List study found.

Tom Myers, executive director of Community Services Agency in Mountain View, said he sees the impact of the squeeze on the low-income in his city.

“Thirty, forty years ago if you walked down Castro Street you would see a much more diverse community, economically,” he said.

Myer’s organization provides emergency financial assistance for rent and utilities, but he said that’s not always enough for people trying to stay there.

“Oftentimes they’ll come in with an apartment in Mountain View but are walking out the door with our assistance to relocate,” he said.

The same thing is happening in Oakland, according to Jahmese Myres, deputy director of the East Bay Alliance for a Sustainable Economy.

“The entire fabric of the Oakland community has changed,” she said.

As residents move further from Oakland in search of more affordable housing, they try to maintain their connections to family, community groups and religious organizations in the city, Myres said. But longer commutes from their new homes leave them with less time to be engaged.

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The Price We Pay: How rising housing costs are transforming the Bay Area

Where in the Bay Area can you afford to rent on $100,000? Gabaldon said she saw the same thing in Concord, where new arrivals would drive back to Oakland or San Francisco to eat out or go grocery shopping. She said she’s seen the negative impact that has on small businesses, like the liquor store where she works part-time as a bookkeeper and has watched sales decline.

But she does the same thing now, still driving to the restaurants, grocery stores and Mexican bakeries she likes in Concord.

“I still commute over there to just get whatever I need,” she said, “because I feel like I’m at home over there.”