Chumra of “נתן סאה ונטל סאה ”
38. In a previous Chukai Chaim issue (269, par. 15), we wrote at length about the concern of נתן סאה ונטל סאה . We mentioned that for a tevila d’oraisa, it is proper to be machmir and consider it posul in a case of נתן סאה ונטל סאה in accordance with the Ra’avad’s opinion (רשב''ץ הובא בש''ך סקס''ג, שו''ת דברי חיים הל' מקואות אות כ', שו''ת מנח''י ח''ב סי' כ''ג ).
39. Keilim mikva. Some point out that this chumra should also apply to tevilas keilim, which is d’oraisa according to most poskim, (Issue 93). However, we do not see anyone in the world strictly makpid on this (מו"ר בעל קנה בשם, היכל הוראה ח"ד הוראה קי"ב, חוט שני הל' טבילת כלים עמ' ל"ה ). Sometimes they add a “bor hashaka” [40 sa’ah of rainwater connected to the mikva with a pipe], which helps somewhat, but they do not do it with every detail, e.g., an additional bor hashaka or bor al gabei bor etc. Perhaps this is because it does not come with the severity of kareis. The main reason is that when people toivel their dishes, mikva water comes out of the mikva in the dish and gets spilled back into the mikva. After a short time, the water has the p’sul of נתן סאה ונטל סאה. Since this is unavoidable, people are not makpid on it.
In the Rain
40. “זחילה נכנסת .” A mikva’s water must all be sitting in one place. If water flows out of the mikva, the mikva is posul. There are many intricacies regarding where the water is moving from, how much water makes it posul, etc. The Divrei Chaim (הל' מקואות אות ה' ) has a well-known chumra which also considers זחילה נכנסת posul, i.e., the mikva is posul even when water runs into the mikva. This chumra has been taken on – at least l’chatchila – by high-level mikva’os for d’oraisa tevila (שו"ת שואל ומשיב מהדו"ת ח"ג סי' מ"ז ד"ה וקנה, דרכ"ת סי' ר"א סקי"ג, חיבור לטהרה כלל ב' אות מ"ב, שו"ת דברי יציב יו"ד סי' קי"ד וקט"ז ).
41. Based on this, some rule one may not toivel dishes in an outdoor, uncovered mikva during the rain due to זחילה נכנסת (הגר"מ לוינשטיין, גליון מרבה תורה פ' יתרו ). However, we have never heard of such a thing. It is clear that people always toiveled in collected waters, rivers, and the like, and did not avoid doing so in the rain. This is clearly not called זחילה נכנסת since the water comes straight from the sky and does not flow over anything.
