This week, we're exploring the San Francisco Bay Area and the way income inequality is affecting the region. Check out the other pieces of the week, aggregated on this page.

Santa Clara County, Calif., is home to Google, Apple and eBay. So it's no surprise that the median household income was $91,000 a year in 2012, one of the highest in the country. Yet one-third of the households in the county don't earn enough for basic living expenses, even when they work at some of those big tech companies.

Take Manny Cardenas, a security guard at Google who lives in low-income housing in San Jose and commutes regularly to Google's sprawling corporate campus in Mountain View. Cardenas, a stocky, soft-spoken 25-year-old, has been working as a part-time security guard at the search giant for the past year and a half.

Most of the time, he guards a parking lot during special events at the nearby Shoreline Amphitheater.

Cardenas says his job is to "make sure none of the people were parking in Google's parking place." He says he usually stands in the lot for eight hours and gets a lunch break. That gives him a chance to dive into Google's famous free gourmet food buffet; he would like to bring a few snacks home for his 5-year-old daughter, but as a contract worker, he can't.

"I see people taking to-go boxes," he says. "They give you to-go boxes if you ask for them, but we weren't allowed to do that."

Cardenas says it is strange being on Google's campus, watching the regular employees drive around on company-supplied bikes and scooters and taking food home.

"You feel like you're different," he says. "Even though you're working in the same place, you're still like an outsider. And it's weird because you're actually protecting these people."

Cardenas earns $16 an hour, has no benefits and never gets more than 30 hours a week. In a good month, he brings home about $1,400. If Cardenas didn't live with his mother, he says, he probably wouldn't have a roof over his head.

Sometimes Cardenas says he doesn't get much notice if his employer wants him to work a shift, and because he shares custody of his daughter Zoe with her mother, and he picks her up from school four days a week, that can mean turning down money.

"If they call me for a shift on the same day I have to pick up my daughter, I can't do that shift, and therefore I'm not going to get paid," he says, "so it's very difficult and to then be a parent."

Sometimes, Cardenas says, he doesn't make enough money to feed himself and his daughter, which feels strange, working at a place like Google.

"Like, I was thinking, 'Wow! If I was just one of them, I wouldn't need to do any of that.' They get to eat whatever they want, however they want."

Cardenas has had to rely on a food pantry — Sacred Heart Community Service in San Jose — a few times. According to its executive director, Poncho Guevara, it is common to see others like Cardenas there.

Last year, 38 percent of the jobs created in Silicon Valley paid $18 an hour, Guevara says. "It sounds like a considerable salary," he says, "but it's really not enough to be able to make ends."

It's expensive to live in Santa Clara County. According to the nonprofit Working Partnership USA, a single person with no dependents needs to make $16.50 an hour, plus benefits, just to have the basics of living.

Cardenas works for a security contractor called SIS, which has contracts with big tech companies including Apple, Twitter, eBay and Google. According to SIS, more than half of its workers are part time with no benefits. NPR reached out to Google, Apple and Twitter about pay for their security guards, and none responded.