There’s the wealth gap, the gender pay gap, the skills gap. Now you can add the Silicon Valley benefits gap to the list.

A growing focus on health and wellness has tech giants offering benefits like flexible sick- and family-leave policies, on-site medical clinics and even egg-freezing to its armies of coders, designers, engineers and product managers. In many cases, though, this largesse stands in contrast to the level of support that drivers, maintenance workers or cafeteria staff get.

Labor advocates say that since many service workers are employed by third-party contractors who have to compete with low bids to win business, they miss the Silicon Valley benefits gravy train.

“We’ve got companies that make stupendous amounts of money and can afford to treat them better,” said Rome Aloise, principal officer of Teamsters Local 853 in San Leandro, Calif. The Teamsters is seeking to organize shuttle drivers who work at tech firms through third-party contractors.

The divide between haves and have-nots in Silicon Valley can be subtle. Although shuttle drivers can earn around $18 an hour, they still don’t make enough to live anywhere near their jobs. The communities where their homes, kids’ schools and doctor’s offices are located are so far away that it’s hard to take advantage of health benefits even if they do have them. Carving out time for a doctor’s appointment for themselves or their kids means an elaborate calculus of scheduling, lost wages and the money in gas and tolls incurred from a second round trip.

“The fact is most of these people work so far from where they live that it’s probably not feasible,” Aloise said. “None of these people can afford to live within probably 40 miles of where they work.”

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Tech employees who are ferried to and from work by contract drivers are far less likely to face such problems. About half the big tech firms surveyed by HR consulting firm TowersWatson now have some kind of on-site health care provider, and more are adding on-site vision and dental services. This year, TowersWatson said, companies in the tech and telecom sectors will spend an average of $10,450 per employee on health care expenses, nearly $1,000 more than the average per-employee cost across employment sectors.

“[Health perks] have a lot of value to employees because they create a lot of convenience,” said Vincent Antonelli, a senior consultant at TowersWatson. On-site medical care is worth the investment, since an engineer or product manager doesn’t have to carve out an entire afternoon for a doctor visit. Letting employees work alternate hours or telecommute is also on the rise, keeping workers productive even if they have to take care of a sick kid.

“None of these people can afford to live within probably 40 miles of where they work.”

This is another place where the lives of Silicon Valley’s elite and the working class diverge. Former security guard Manny Cardenas said he was getting ready to leave for work when he got a call from his daughter’s school, telling the 25-year-old single father that she was sick and to come pick her up.

Cardenas, who said he was juggling college coursework with a “flex” shift schedule that left him with little predictability or advance notice of his hours, typically relied on his mother to bridge the childcare gap. That day, she couldn’t help out. Cardenas forfeited his shift, losing the income and earning a reprimand.

“They said if it happened like that again, I would be written up,” he said. Cardenas earned his bachelor's degree earlier this year and now works at a nonprofit.

Although activists in San Francisco, where many highly paid Silicon Valley workers live, have protested tech companies' private shuttles as a symbol of the area's growing inequality, the quiet work-life balance conflicts faced by blue-collar workers fail to attract the same degree of concern, said Alfredo Fletes, a representative for the Service Employees International Union — United Service Workers West.

“San Francisco residents, they take out their anger on these large buses, but there’s this whole swath of workers on these campuses who are invisible to the tech industry’s critics,” he said.

The SEIU wants security guards to be in-house rather than provided by a third-party contractor, a step recently taken by Google. “We are looking forward to making these valued positions both full- and part-time Google employees,” a company spokesperson said in a statement via email. The company is shifting about 200 security guards from contractor Security Industry Specialists when its current contract is over.

Google denied that SEIU involvement played a role in its decision, but Fletes said the change sends a strong pro-worker message. “It’s a sign that tech companies are starting to realize they have to provide good jobs at all levels,” he said.

In the future, Fletes suggested, the issue of working conditions for service personnel could be as much a part of tech companies’ recruitment pitches as on-site fitness evaluations or dental exams.

“They’re mission-driven companies and they care a lot about their image,” he said. “It plays a lot into their recruitment of talent.”