A few weeks ago, dog walker Kelly Marshall led his seven dogs to an open field between 38th and 39th Streets NW in Glover Park. Though the field is officially a spur of Rock Creek Park and owned by the National Park Service (NPS), it’s a de facto dog park widely used by the army of walkers that service the Northwest quadrant. The drinking fountain in the park’s southwest corner, installed by the NPS, even features a ground-level water bowl so doggies can lap water along with their masters.

Marshall says that as he approached the park, two park rangers removing an old mattress from the woods stopped him. “Are you a dog walker?” the ranger asked, according to Marshall. “Because it’s illegal to run a business on federal land without a permit.”

The ranger told Marshall that he was not allowed to take the dogs into the park—leash or no leash. When Marshall asked how he could obtain a permit, the ranger told him that the NPS doesn’t issue them for dog walkers. Earlier that day, another walker who had his dogs off leash was threatened with the impoundment of his dogs.

“The things that people get harassed or ticketed for are for having dogs off leash,” says Marshall. “This is the first that I’ve ever heard of people harassed for having a business on federal land.”

NPS spokesman Bill Line says that the ranger was correct in his interpretation of the law. “If someone wants to operate a dog-walking business and make money off it…and you are using the park on a regular basis to walk the dogs, you’re coming pretty close to or crossing the line of constituting a business,” he says.

Since all the canine traffic could harm the park, the NPS has the authority to require a permit. “Many people who do walk dogs don’t pick up their dogs’ poop,” Line adds. “Is it fair to the next visitor to walk in that dog’s poop? Would you want to walk through that poop?”

Line says that permits can in fact be obtained by calling the NPS’ Office of Park Programs. Marshall, however, merely waited until the rangers loaded the mattress into their truck and then sauntered into the park. “I was like, whatever,” he says. “As soon as…they had left, I took the dogs off leash.”