This perek (chapter) and this Mishnah are going to be about how a person has to make sure that he doesn't damage his friend's property, even if he's dealing with his own property. In other words, if a person's own property is going to put his friend's property in a situation where it could get damaged, he has to do certain things on his own property to avoid causing damage to his friend's property.
We'll talk about various types of irrigation systems or holes being dug into the ground on a person's own property that may affect his neighbor's property. A person is not allowed to dig a pit where he would store water near the edge of his property, which would also be next to his neighbor's property. He's also not allowed to dig a ditch or a square vault where there would be a roof and an opening, or an irrigation ditch or a laundering pool near his neighbor's pit, because he could damage his neighbor's pit by building or digging a hole on his own property. He could cause his neighbor's pit to fall in. The shaking or collapsing could happen through his own work. Also, if the water that he's storing gets too close to his neighbor's hole, it's going to cause a hole in his property. It's going to soften the dirt that's between them, and everything is going to fall in. So he's not allowed to do that. He has to have distance between his pit and his neighbor's pit, unless he distances the edge of his pit from the edge of his friend's pit or property. He has to be at least three tefachim (handbreadths) away from his friend's property to make sure that even if his friend—let's say there's no pit even there right now, but a potential pit that his neighbor would fall in—he'll be put there at some point in time. We're worried about that as well. So he has to have a three-tefachim boundary or setback from his friend's property. He also has to coat the inside of his pit with lime to make sure that it's tough and strong and that no water will seep out and damage his friend's pit.
Now we'll also talk about materials that are not allowed to be stored near a brick or stone wall of a neighbor. Marchikin et hagefet ve'et hazavel ve'et hamelach ve'et hasid ve'et hasela'im mikotlo shel chaveiro shlosha tefachim. A person has to put away, put to the side, any piles of olive pulp. That means after you've pressed it for olive oil, or manure, or salt, or lime, or different types of stones, flintstones that would produce fire. Those have to be set back at least three tefachim from the wall of his neighbor because these items produce a lot of heat and could damage the wall of his neighbor. So he has to put them away so they won't damage that wall.
Or, o sad besid. The second option that the Mishnah offers: you could also just coat your neighbor's wall with a thin layer of lime to protect it from the heat. So it's either or: distance these items from the wall or sort of insulate that wall and make sure that it doesn't get damaged by these items.
We'll also talk now about different actions that you're not allowed to do too close to a neighbor's wall. Marchikin et hazera'im, marchikin et hazera'im ve'et hamacharisha ve'et mei raglayim min hakotel shlosha tefachim. A person has to keep a distance of three tefachim from his neighbor's wall when planting seeds, plowing, or urinating—going to the bathroom—because any of these types of things, if they're done too close to his neighbor's wall, could weaken it. If a person is planting close to the wall, then the roots may go and break the foundation of that wall. Plowing also could damage the foundation. Urinating near the wall could dissolve the bricks. Urinating there is only allowed when you're at least three tefachim away because the wall could be built from something soft, and it could damage it.
We'll now list two different items that have to be kept away from a neighbor's wall. U'marchikin et harechayim. You have to distance your millstone from your neighbor's wall. You have to set them up so that the wall is far away. Shlosha min hashachav. Three tefachim from the lower stone of the millstone. Shehen arba'a min harechav, which is four tefachim from the upper stone. You have to distance it away because the vibrations caused by the millstone could possibly shake the ground and weaken the wall, so they have to be set back.
Ve'et hatanur shlosha min hakelia shehen arba'a min hasafa. An oven has to be distanced from a neighbor's wall as well, so that the wall is three tefachim away from the bottom of the base of the oven and four tefachim from the upper lip of the base, because the heat of the oven could be harmful to the wall. So you need to set it far back from your neighbor's wall.