713. Drinking from a Different Domain

Shabbos 15:2

One may not stand in a private domain and stick his head into a public domain to drink, nor vice versa. His head and the major part of his body must be in the domain from which he is drinking. This applies when one drinks with nice vessels that he needs. In such a case, the Sages were concerned that one might transfer the vessels from one domain to the other. If he uses insignificant vessels that he does not need, then only his head need be in the domain from which he drinks. If a well of water is in a carmelis, one need insert only his head even when using nicer vessels.

Shabbos 15:3

If water is flowing from a drainpipe or a wall, a person standing in a public domain may catch it in the air and drink so long as he does not touch the pipe or the wall in order to catch the water. If he does touch the pipe or the wall, then the following applies: If the place he touches is higher than ten handbreadths (about 30”) and within three handbreadths of the roof (about 9”), it is prohibited. This is the same as removing water from the roof, which is a private domain. If the drainpipe is four handbreadths by four handbreadths (about 1’x1’) and he caught water from it, it is prohibited regardless of the height of the pipe. Nevertheless, one is not liable in such a case because the water is flowing and not at rest.