New York City has one of the largest sanitation departments in the world, but, with declining landfills, we follow waste from sidewalks and garbage trucks to treatment facilities and upstate farms.  It is a civic drama that plays out each morning on sidewalks across New York City.  A dog sees a bag of garbage set out for collection. He feels compelled to relieve himself on it.  The dog’s owner, distracted or indifferent, stands idly by.  And along comes a sanitation worker, cursing silently, or not so silently, as he hefts the glistening bag.  “How would you like it if I came to your office and peed on your desk?” a sanitation worker named Tim asked as he made his rounds on a recent morning in Park Slope, Brooklyn. “It’s the same thing.”  It doesn’t matter if the neighborhood is fancy or gritty.  “You swing the bag to throw it in the truck and you get urine all over your partner,” a garbage truck driver named George said on a tenement-lined block of East 146th Street in the South Bronx last Monday. “Who wants to be hit with urine?” (Like other sanitation workers, he would not give his last name because of department rules against talking to the press.)  “I’ve had people, while I’m picking up the bags, they walk up and let the dog pee on the bag,” a trash collector named Kevin said as he paused before a townhouse on Charles Street in the West Village.  “Sometimes you point it out to them and they’re apologetic,” he said. “Sometimes, they’re like, ‘This is where he does it.’ ”  Those at the other end of the leash mostly said they did not see what the fuss was about.  “Why not? It’s garbage,” David Velasquez, 28, a dog walker, said as he escorted a Great Dane and a tan-and-white mutt along Charles Street. “I’m all right with it.”  At St. Mary’s Park in the South Bronx, Rich Cruz, who owns two pit bulls, said that dog urine was actually “probably beneficial” to sanitation workers because, he said, it repelled rats.  “The rodents smell the dogs and then they won’t tear open the trash,” Mr. Cruz said.  On Warren Street in Park Slope on one recent evening, a black-and-white Japanese spaniel made his way up the street, sprinkling a few drops on each bag like a chef salting a line of steaks.  “It’s part of our urban environment,” his owner, who declined to give his name but identified himself as a commercial real estate broker, said by way of explanation. “Even if there was a law, there’s not much you can do about it.”  In fact, there is a law, sort of.  Section 161.03 of the city’s health code forbids pet owners to let their animals “commit a nuisance on a sidewalk of any public place.” The long list of “nuisances” includes urine.  But in practice, a city health official said, the law is enforced only in cases that pose a serious public health risk.  Even so, the the Sanitation Department’s official position on the matter is: Please don’t.  “When nature calls for our four-legged friends,” the department said in a statement, “we’d ask that all New Yorkers try to steer their dogs away from garbage and recycling bags left at curbside and awaiting collection.”  Why do dogs want to urinate on trash bags anyway? Alexandra Horowitz, the author of “Inside of a Dog” and the director of the Dog Cognition Lab at Barnard College, offered several reasons.  The bag, she said, is a new feature on the dog’s landscape and therefore inherently interesting. It smells like food. And because it sits above ground level, it acts as a sort of broadcast tower for a dog’s scent marking (see also: hydrants, lampposts).  “He’s thinking, ‘This trash smells good, but it can smell like me!’ ” Dr. Horowitz said.  There are, of course, dog owners who try not to let their charges near trash bags.  “Think of the guy who’s got to pick it up,” said Bernard Jaye, who was walking his daughter’s pit bull outside St. Mary’s Park.  “It’s like raising kids,” said Melissa Cicetti, an architect out with an Australian shepherd and a Border collie in Red Hook, Brooklyn. “I’m a very polite person, so I teach my dogs to be polite.”  But mostly, the nays seemed to be outnumbered.  On Butler Street in Park Slope, as Tim the sanitation worker aired his grievances, a tall, sad-faced boxer (dog, not human) paused at a trash bag and left a puddle on it, as his owner, Hector Saez, looked on.  “Perfect,” Tim said with a roll of his eyes.  Mr. Saez shrugged. “The dogs will go where they go,” he said.
Like fire hydrants and lampposts, trash bags put out for collection are popular targets for dogs. But unlike those curbside fixtures, the bags must be picked up.