Tohoros 6:6-7

Tohoros 6:6

A case of doubt in a private domain is ruled unclean unless the person says that he didn’t touch the impurity; a case of doubt in the public domain is ruled clean unless the person says that he did touch the impurity. The paths to Beis Gilgul and similar places are considered private domains vis-à-vis the laws of Shabbos and public domains vis-à-vis the laws of ritual impurity. Rabbi Elazar says that the Sages only mentioned the paths to Beis Gilgul because they’re considered a private domain for both things. The paths that open to wells, cisterns, caves and wine presses are considered private domains vis-à-vis the laws of Shabbos and public domains vis-à-vis the laws of ritual impurity.

Tohoros 6:7

A valley in the summer is a private domain vis-à-vis the laws of Shabbos and a public domain vis-à-vis the laws of ritual impurity. In the rainy season it is considered a private domain for both things.