What is meant by an unresolved doubt regarding drawn water that our Sages ruled as pure? A mikveh about which one was unsure whether drawn water fell into it. Or even if one was certain that drawn water fell into it, but was in doubt whether there were three lugim or not. Or even when one was certain that there were three lugim of drawn water, but there was a doubt whether the mikveh into which the water fell contained 40 se'ah or not. In all instances, the mikveh is acceptable.
The following law applies when there are two mikveot, one containing 40 se'ah and one containing a lesser amount. Three lugim of drawn water fell into one of them, but it is not known into which they fell. Because of the doubt, we rule that the acceptable mikveh is pure, because there is a factor on which one can rely. If they both contained less than 40 se'ah and three lugim fell into one of them, they are both disqualified, because there is no factor on which one can rely. If the drawn water fell into one, it would be disqualified and if it fell into the other, it would be disqualified.
When one left a mikveh empty, and returned and found it full, it is acceptable, for there is an unresolved doubt whether the water for this mikveh was drawn.
When a pipe carried water into a mikveh, but there is a mill next to it, if there is a doubt whether water flowed into the mikveh from the pipe or from the mill, it is unacceptable, because the disqualifying factor is evident. If, however, the mikveh contains a majority of acceptable water, it is acceptable because the doubt involves drawn water and there is an acceptable mikveh whose presence had been established.
❓ Doubt = Purity (for Mikveh)
Regarding mikveh validity, the Sages ruled leniently on doubt: a mikveh about which there is uncertainty whether drawn water fell in is considered valid. Even two mikveot where it is unknown which one received the drawn water — both are treated as valid. A mikveh left empty and found full upon return is valid. A mikveh near a mill where the source is uncertain: if the mill is the known disqualifying factor, it is invalid.
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Location-Based Presumptions — Nations' Lands vs. Eretz Yisrael
All of the mikveot found in the lands of the nations are invalid for immersion, for we operate under the presumption that the water is drawn. All of the mikveot found in Eretz Yisrael, in the cities, within the gates are assumed to be invalid, because the inhabitants of the cities wash their garments in them and pour drawn water into them at all times. All of the mikveot found in Eretz Yisrael outside the gates of a city are presumed to be pure. For it is assumed that they came from rainwater.
🗺️ Where You Are Matters
All mikveot found in lands of the nations are presumed invalid — their water is assumed drawn. In Eretz Yisrael, mikveot in walled cities are presumed invalid; in open settlements and fields they are presumed valid. One should not immerse in the nations' lands unless there is a known valid mikveh.
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Doubts About the Immersion Itself and Sequential Immersions
In all the following situations, when an impure person descends to purify himself and: a) there is a doubt whether he immersed or did not immerse, b) even if it was known that he immersed, but there is a doubt whether the mikveh contained 40 se'ah or not, or c) there were two mikveot, one containing 40 se'ah and one that did not contain 40 se'ah, he immersed in one of them and did not know in which one he immersed, he is impure because of the doubt. The rationale is that we presume that the impure person is impure until it is certain that he immersed in the proper manner. Similarly, if a mikveh was measured and it was discovered that it did not contain the required amount of water, whether the mikveh was located in the public domain or a private domain, all of the pure articles that were immersed in it are considered as impure retroactively until a time when it was measured and it was complete. When does the above apply? When the immersion was intended to purify the person or the article from severe impurity. When, however, the immersion was because of a light impurity, e.g., one ate impure foods or drank impure beverages, his head and the majority of his body entered drawn water, or three lugim of drawn water fell on his head and on the majority of his body, since the primary aspect of these types of impurity are Rabbinical in origin, he is pure despite the doubt, as we explained. Even though the person is in doubt whether he immersed or not, the mikveh in which he immersed was discovered to be lacking afterwards, or other doubts of this nature arise, he is pure.
When there were two mikveot, one kosher and one unacceptable, a person immersed in one to purify himself from a severe type of impurity, and touched pure foods, their status is questionable. If he immersed in the second mikveh as well and touched pure foods, the status of the first remains questionable as before and the second ones are pure. If these two batches of foods touch each other, the status of the first remain questionable and the second should be consigned to fire. This ruling also applies if in the interim he contracted impurity from a light source of impurity, as we explained, immersed in the second mikveh and touched pure foods. If, however, he immersed in one of the mikveot because of a light impurity and then touched pure foods and then contracted a severe type of impurity, immersed in the second, and then touched pure foods, the first batch are pure and the status of the second is questionable. If these two batches of foods touch each other, the first should be consigned to fire and the status of the second remains the same as before. The following rules apply if one of two mikveot contained 40 se'ah of acceptable water and the other was filled entirely with drawn water and two people immersed in them without knowing which one immersed in the acceptable mikveh and which immersed in the unacceptable one. One of the two had contracted a severe type of impurity and one had contracted a light type of impurity. They both touched pure foods. The status of the foods touched by the one who immersed because of a severe type of impurity is questionable, but those touched by the one who immersed because of the light type of impurity are pure. In the situation described in the above clause, if one person was impure and descended to immerse and the other was pure and descended merely to cool off, pure foods touched by the one who descended to immerse in one of them are of questionable status, as we explained. And the one who descended to cool off is pure as he was previously. The rationale is that this is a doubt concerning drawn water, for the question is: perhaps he immersed in the pool of drawn water when he cooled off and thus contracted impurity.
The following rules apply when there are two mikveot, each containing 20 se'ah, one of drawn water and one of acceptable water. If a person cooled off in one of them and then touched pure foods, they are considered pure. If afterwards, he cooled off in the second and touched pure foods, they should be consigned to fire. For his head and the larger greater of his body certainly entered drawn water, as we explained.
🤷 Did I Immerse Properly?
If one doubts whether he immersed, or whether the mikveh had 40 se'ah, his status is uncertain — he may not touch pure foods until re-immersing. Two mikveot — one kosher, one invalid — a person immersed in one, then touched pure foods, then immersed in the other: the foods he touched between immersions remain questionable. Two mikveot each with 20 se'ah — one drawn, one valid — if one cooled off in one, the pure foods remain pure; if one then immersed in the second, they are pure even if he originally immersed in the drawn one.
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🎓 Key Principles
Chapter 10
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Doubt Favors Validity for Mikveh Status The Sages ruled leniently regarding mikveh doubts — uncertainty about whether disqualifying water fell in does not invalidate the mikveh.
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Geography Creates Presumptions Mikveot in non-Jewish lands are presumed invalid (drawn water); those in open settlements in Eretz Yisrael are presumed valid.
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Sequential Immersions Can Resolve Doubts Immersing in a second mikveh after touching uncertain pure foods restores the purity of those foods, as the combined immersions resolve the original doubt.
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Known Disqualifying Factors Shift the Rule When a known source of disqualification (such as a mill) is adjacent to a mikveh, the leniency of doubt does not apply — the presence of a known problem renders the mikveh invalid.