Reference for Mikvaot 2:6

הַמְסַנֵּק אֶת הַטִּיט לַצְּדָדִין וּמָשְׁכוּ מִמֶּנּוּ שְׁלשָׁה לֻגִּין, כָּשֵׁר. הָיָה תוֹלֵשׁ וּמָשְׁכוּ מִמֶּנּוּ שְׁלשָׁה לֻגִּין, פָּסוּל. וְרַבִּי שִׁמְעוֹן מַכְשִׁיר, מִפְּנֵי שֶׁלֹּא נִתְכַּוֵּן לִשְׁאֹב:

One who removes the plaster [from the floor of <i>mikveh</i>] to the sides, and three <i>log</i> [of water] flowed from it [from the plaster], it is valid. If one removed [the plaster from the waters of the <i>mikveh</i>] and three <i>log</i> flowed out from it, it is invalid [since they are considered drawn waters]. And Rabbi Shimon considers it valid it because one did not intend to draw [the waters in such a case].

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