You're walking your four-legged pal around the neighborhood and he lifts his leg on your neighbor's tree. Do you shrug and wait for your pet to finish things up or do you frantically pull on the leash and hope no one was peeking out the window?

Most responsible dog owners head out on walks with a roll of poop bags, but what happens when your pup's business is of the less obvious variety? People are divided on proper pee etiquette. Here are answers to some common dog-meets-lawn questions.

What's the law? The first pooper-scooper law went into effect in New York City in August 1978. The Canine Waste Law, as it was officially called, required dog owners to clean up their dogs' poop, and it was a model for other cities, including San Francisco, Boston, Dallas and Houston. But there's no major law on the books, as far as we can tell, requiring people to mop up their dog's urine.

What damage does it do? You know what the obvious problem is with poop: It's gross, it stinks and someone could step in it. But what's the harm in a little urine that soon trickles away? It's all in the nitrogen. A dog's urine has a high concentration of nitrogen, which is created when the proteins the dog eats are broken down naturally by his body, writes Dr. Steve Thompson, director of Purdue University's Veterinary Teaching Hospital. A small amount of urine, like a small amount of nitrogen in lawn chemicals, can act as a fertilizer and result in a bright green patch of lawn. But a large amount can cause the lawn to turn brown in those spots, either injuring it or causing it to die.

When a dog picks a spot to relieve himself, it's often a calling card to other dogs to choose the same area. So more and more dogs add more and more nitrogen, which can do a serious amount of damage.

Does the dog's sex matter? Many people believe that only female dogs cause spotting on lawns. That's not totally true, according to the Colorado State University Extension. Dog spotting is caused most often by dogs that squat. That's because they typically deposit a large amount of urine at one time all in one area. Although that's often what female dogs do, some male dogs squat too, especially if they're very young.

Sometimes lawn damage caused by a squatting dog will have a brown spot in the middle surrounded by a green ring on the outside. Horticulturists sometimes refer to this as "female dog spot disease," according to Purdue's Thompson. The strong nitrogen levels at the center of the spot cause the grass to burn, but because the urine is diluted toward the outside of the circle, it has a bit of a fertilizer effect, causing the grass to turn green.

Sometimes if male dogs repeatedly choose the same young bush, tree or vine as a marking post, the nitrogen overload that hits that spot over and over may cause it to die, Thompson says.

Does the dog's breed matter? No, says the Colorado State University Extension. The only thing that matters is the size of the dog. The bigger the dog, the bigger the bladder.

Can you prevent damage? Pet owners have tried all sorts of home remedies to modify their dog's diets in hopes of causing fewer lawn problems. Some try adding supplements like baking soda or potassium citrate to make their pet's urine less alkaline. However, as experts at both Purdue and Colorado State point out, the pH of the urine has no effect on what happens in the lawn. And, instead, these supplements might hurt your dog's health. Other people try adding salt, garlic or tomato juice to their dog's diet in hopes of making their pet thirsty, so they will drink more, thus diluting their urine. But salt, for example, can be dangerous for older dogs and pets with some health conditions, so consult your vet before making dietary changes.

Can you fix the spots? Once the leg has been lifted, there's little you can do, say the experts. Some people have tried sprinkling baking soda or gypsum; others have tried squirting on a little dishwashing liquid. (Imagine explaining that to your neighbor.) But the only thing that can help is immediately flooding the area with water.

In fact, one Reddit user says that's what he/she does when going on dog walks:

"I personally try and get my dogs to do their business in a safe zone before we do neighborhood walks, but I also realize planning bathroom breaks for dogs probably isn't fully realistic when outdoors with access to turf. Because of that, I bring water with me when I do neighborhood walks or walks on the town and I water down any pee spots," posted a user named dog_face_painting in a vibrant discussion about whether or not it's a big deal to let your dog pee on someone else's property.

"I also spent time going door to door in my neighborhood to ask if anyone preferred my dogs to stay off their lawn during neighbor walks. I won't let my dogs on their lawn if I know they don't want them there ... I think the reasonable position is to realize dogs are dogs, and people can try and be respectful of property, but it might not always pan out. Just try to be conscientious, on both sides."

(We want to live in that neighborhood!)

Mary Jo DiLonardo Mary Jo writes about everything from health to parenting — and anything that helps explain why her dog does what he does.