….Contractors on federal land are supposed to make a bit more than that — but over the years, the laws that require it have been sparsely enforced and widely violated. And loopholes make sure fewer workers are covered in the first place. Take Glover. Groundskeepers are covered by the Service Contract Act, which dictates that they be paid a “prevailing wage” set by the Department of Labor. In D.C., the wage for groundskeepers is $13.07 — which would make a big difference to Glover, who lives on a cot in his sister’s basement in Maryland because he can’t afford his own place. … The Smithsonian Institution, which runs the zoo, says that Service Contract Act doesn’t cover him. Spokeswoman Pamela Baker-Masson says the Friends of the National Zoo, a member-supported nonprofit that employs all the maintenance and concessions workers, isn’t primarily concerned with providing services covered by the Act, so the law shouldn’t apply to the whole contract….. In its complaint, Good Jobs Nation says in total the violations have deprived 65 workers of $1,578,700 in wages at three workplaces over the two years the statute covers. Their findings illustrate the difficulty the federal government has had in enforcing its own laws since they were passed decades ago….