San Francisco and San Mateo counties in the Bay Area have passed a grim milestone reflecting extreme housing costs: The federal government now considers households in the counties which make $100,000 a year to be “low income,” making them eligible for federal housing programs for poor families, most notably Section 8 vouchers that allow

The specific income threshold for the two counties is $105,350 – less than the $115,300 median annual household income of those counties. Strikingly, however, the poverty threshold in the two counties is nearly 90 percent higher than the Census Bureau’s most recent estimate of median U.S. household income ($56,516) and more than 60 percent higher than $64,500, the census estimate of median California household income.

The threshold in the adjacent counties of Santa Clara, Alameda and Contra Costa is between $80,000 and $85,000.

While the change makes more San Francisco and San Mateo households eligible for subsidies, it is unlikely to provide much relief to anyone any time soon. Section 8 vouchers are rationed because of limited federal funding and there are long waits – sometimes decades-long – to qualify in counties across America, especially in high-cost urban areas.

A recent San Jose Mercury-News report on the Housing and Urban Development income-threshold change offered it as hard evidence of the housing affordability crisis that threatens to drive in-demand public school teachers away from the Bay Area and Silicon Valley and toward school districts with similar pay but rents that average much less than the $2,500-plus a month seen in such communities as San Jose, Oakland and Pleasanton.

The report outlined the frustration felt by Demetrio Gonzalez, a Richmond educator with a master’s degree in education who works for the West Contra Costa Unified School District. Gonzalez, who makes $48,000 a year, says he has no choice but to share a house with four roommates.

“With this income, I don’t think it is possible to create a future in the place I love and the place I work,” he told a Mercury-News reporter. “When I decide to buy a home — if possible — I’ll have to look elsewhere.”

Housing costs exacerbate Bay Area teacher shortage

Such stories add a new dimension to reports of teacher shortages throughout the Golden State. Three-quarters of California school districts reported struggling to fill vacancies entering the 2016 school year, according to a report from the California School Boards Association and the Learning Policy Institute. This has led to an unparalleled used of technically unqualified teachers in state public schools, especially in math, science and special education.

During the 2015-16 school year, the report said the state authorized 10,200 teachers without the normal baseline credentials to teach various subjects – more than double the number seen in 2012-13.

But the struggle to fill teacher positions appears far more daunting in the Bay Area and Silicon Valley than the rest of the state. The California Teachers Association described San Francisco as “ground zero” for the state’s teacher shortage.

Last year, to improve teacher retention and to entice new teachers, many districts in the region used a private-sector tactic and supplemented pay with one-time bonuses. The most generous was San Jose Unified: All teachers on the payroll on the first day of the 2016-17 school year who met very basic requirements for coming to work got a check equal to 7 percent of their total annual salary.