תלמוד על עירובין 176:25

Rebbi Jeremiah said, Rebbi Meïr and Rebbi Eliezer ben Jacob both said the same. Rebbi Eliezer ben Jacob as we have stated: “Rebbi Eliezer ben Jacob says, on the Sabbath one may pour water into a sewer which is covered for four cubits in the public domain, but the Sages are saying, even from a roof or a courtyard 100 cubits [wide] one may not pour into the sewer.” Rebbi Meïr as it was stated: In large cities one may pour water into flows even though they are perforated, the words of Rebbi Meïr¹⁴⁰If a river is diverted into many small currents which run in streets and through courtyards (as can be seen, e. g., in Freiburg i. B., Germany), one may pour water into them on the Sabbath since it will not be noticed.. ¹⁴¹The main discussion about prohibitions added because people may get a bad impression, which also includes the text here, is in Kilaim 9:2 (Notes 34–40, Eruvin problem Note 39). Rav’s opinion is accepted in the Babli (Šabbat 64b, 164b, Beṣah 9a, ˋAvodah zarah 12a) but consistently rejected in the Yerushalmi. And it was stated thus, if it was a drainpipe it is permitted; in the rainy season it is permitted¹⁴²Babli 88b. The Babli holds that during the rainy season there never was any rabbinic prohibition because everything is being wet anyhow.; streaming spouts are forbidden and Bar Qappara stated, if it occurred at a hidden place it is permitted. This disagrees with Rav and he cannot explain it, since Rav said that everything forbidden because of a bad impression is forbidden even in the most private room.