Siman 217

One who sells to his fellow a place within his field so that the buyer may make a water channel in it to irrigate from it a beit hashalachim—which is a field that is not satisfied by rainwater alone—he must give him a span of four amot by four amot. For the span of the digging of the channel is two amot, and from each side he requires an amah for its banks, in order to repair the channel from that soil of the banks if its walls fall. And some say that three amot are sufficient, for the span of the channel itself is only an amah by an amah [Tur]. And if he sold him a water channel to irrigate with a kilon—which is for watering animals and washing clothes, which does not require such a great span—he gives him two amot: an amah for the main channel and half an amah from each side for the banks to repair. And according to the "some say," he only requires an amah and a half, for the channel itself is only half an amah [ibid.]. And these banks do not belong absolutely to the owners of the channels; rather, they belong to the owner of the field, only that he is not permitted to sow them because the seeds loosen the soil and will ruin the channels. But he is permitted to plant them, for plantings do not ruin them for the time being. And even though they designated the banks for the owners of the channels to repair the channels from them, nevertheless, if the banks are exhausted, the owner of the channel may repair it with the soil from beyond the banks. For the sages, of blessed memory, said that on this condition the seller accepted upon himself that this person shall make a water channel in his field: that he shall repair it from the soil in his field. However, initially they established the banks so that the seller should not sow them nor do anything there that has the potential to ruin the channel, because for the most part this measure is sufficient; but when it is not sufficient, he may repair from the soil in the entire field. And that which is explained in the Gemara [Bava Metzia 107b] that the banks of an anigra are four amot—this is a canal and is much larger than a water channel [Tosafot Bava Batra 99b]; therefore, its banks are also larger.

There is reason to doubt when the water has been exhausted from the channel, such that it is no longer possible to collect water into it, whether the place of the channel belongs to the buyer, or perhaps since he only sold it to him for the purpose of the water, it is possible that when the water is exhausted, the land returns to its owner. And similarly in our lands, when a person buys [the right] to dig a well in the domain of his fellow and over the course of time the spring is exhausted, whether the land returns or not. And it appears that it belongs to the buyer [and so it is implied from the Sma, subsection 12, see there].

One who says to his fellow, "I am selling you a pit and its walls," he must give him the width of the wall as three tefachim, for this is its measure, as has been written in siman 155.

One who sells to his fellow a path within his field and did not specify what the width shall be: if he sold him a private path, such as to walk on this path to his house or to his field, he gives him two and a half cubits of width so that a donkey with its load may stand there and pass on this path without hindrance, for this is the approximate width of the donkey and the load protruding from it. And if he purchased the path in order to travel on it with a wagon, he requires four cubits of width. And if it is only to walk by foot, one cubit of width is sufficient [it appears to me]. And this fact, that two and a half cubits is sufficient for a donkey with its load, is when the partitions are not defined, meaning that there are no high partitions on both sides, for then even if the load protrudes slightly more, we have no concern; but if there are partitions from the sides, he must give more according to the assessment of the experts. And if he sold him a path to travel from city to city, he gives him eight cubits so that two wagons will not collide [Sma]. And if he sold him a public path, he gives him a width of sixteen cubits, for this is the path of a public domain regarding the matter of Shabbat, as is explained in Orach Chaim siman 345. And if he sold it to him for a station, which is a place where they stand upon their return from the burial of the dead according to their custom, as there was a specific place for this, he gives him an area of four kavs; and among us, there is no specific place for this.

One who sells a place to his fellow to make for him a burial place, or one who receives from his fellow to make for him a burial place, makes a cave and opens within it eight graves: three from here, three from here, and two in the wall opposite the entrance of the cave. The measurement of the cave is four amot by six, and every grave is four amot in length, six tefachim in width, and its height is seven tefachim. It follows that between every grave from the sides is an amah and a half, and between the two middle ones are two amot. And he makes a courtyard at the entrance of the cave, six amot by six amot. And so he shall make a cave such as this on the second side of the courtyard opposite the first cave [Tur]. And this is all according to their custom, for every family had a specific burial place where all members of the family were buried, and it was a disgrace for them if one of the family would be buried in another place not among his family graves. Therefore, the sages, of blessed memory, said [Bava Batra 100b]: One who sells his grave, the path to his grave, his place of standing, or his place of eulogy—the members of his family come and bury him against the will of the purchaser and give him the value of the grave. See Yoreh Deah siman 363. And in our times in our country, this is not practiced at all.