951. Pouring Water Into a Courtyard

Eiruvin 4:26

Let’s say that a building has three floors, with one person owning the top and the bottom floors and a different person owning the middle floor. Objects may not be lowered from the top floor to the bottom floor by way of the middle floor because we are not permitted to pass things from one domain to another by way of a third. One may, however, lower objects from the top floor to the bottom floor so long as they bypass the middle floor.

Eiruvin 4:27

Let’s say that two buildings face one another with a courtyard between them into which waste water is poured. The residents of these buildings may not pour water into the courtyard unless they make a common eiruv. If the residents of one building dug a pit in the courtyard to pour water into and the residents of the other building did not, the ones who dug the pit may pour water into it; the others may not pour water into the courtyard unless they make a joint eiruv. If the residents of both buildings each dug a pit, then each may pour water into their own pit even if they did not make an eiruv.