Policies on moonlighting vary by district; some have no written guidelines, while others merely advise teachers to ensure any outside work doesn’t interfere with their duties at school.

In North Carolina, a survey conducted in 2007 found 72 percent of teachers moonlight, whether it’s an after-school job or summer employment.

“There’s a culture of silence,” Hilty said. “Everybody knows that moonlighting goes on and they know it’s part of what teachers do but nobody likes to talk about it very much.”

Michelle Hartman, a language arts and science teacher at a Plantation, Fla., elementary school, is balancing two other jobs, one as an organist with the local Presbyterian church, playing at church services, weddings and funerals, and another doing janitorial work twice a week at her father’s accounting firm.

The single mother has a master’s degree in educational leadership and has been a teacher 15 years. But she says she cannot afford to leave any of her extra jobs, which she said brings in about $6,000 year, in addition to her $46,000 teaching salary.

“I’m tired some days,” Hartman said. “But no matter what, it doesn’t matter because I know I need to be there for the students.”

Yet working an extra job inevitably does take a toll. On top of their work in the classroom, teachers have to grade papers and plan lessons—work they often do at home. One study on teachers who moonlight in Texas cited the case of a teacher who ended up grading papers at the restaurant where she worked. The same study found that all the teachers interviewed reported that moonlighting had a negative effect on their health. In the Texas survey, a majority said moonlighting was detrimental to their work in the classroom.

“Yes, they go 100 percent, but they’re still tired,” said Dave Henderson, a retired professor who worked on the study for many years.

Albert Ochoa, a middle school art and publications teacher in Austin, Texas, works at least five hours a night at UPS as a shipper, a job he’s had since graduating from college in 1977. Even though he is now toward the higher end of the teacher salary schedule, he said he cannot afford to quit either job.

He said he’d have to earn another $2,000 a month in order to support his wife, who is on medical disability, and son, and not work a second job. “I’ve had opportunities to go work full time at UPS and do other things,” Ochoa said. “But I enjoy what I do. I like teaching.”