936. A Well Between Courtyards

Eiruvin 3:21

If a well is situated in-between two courtyards, it is prohibited to draw water from it on Shabbos unless they erect a partition ten handbreadths tall (about 30”) so that everyone will be drawing water from his own property. If the partition is above the water, it must descend at least one handbreadth (about 3”) into the water; if the partition is under the water, it must extend a handbreadth out of the water. This is done so that one domain will be distinguishable from the other.

Eiruvin 3:22

Similarly, if a beam four handbreadths wide (about a foot) is placed over the mouth of the well, a resident from one side may fill a bucket on one side of the beam and a resident from the other side may fill a bucket on the other side of the beam. Even though the water is not divided below, it is still considered that the domains have been separated. This was a leniency that the Sages enacted in the case of water.