According to Scriptural Law, it is permissible to immerse in any collected body of water, as implied by Leviticus 11:36: "a gathering of water," i.e., any gathering, provided it contains enough water for the entire body of a human being to immerse in it at one time. Our Sages measured this figure as a cubit by a cubit by a height of three cubits. This measure contains 40 se'ah of water. According to Scriptural Law, the water is acceptable whether drawn or not.
According to Rabbinic Law, water that is drawn is invalid for immersion. Moreover, if there was a body of water that was not drawn and three lugim of drawn water fell into it, the entire body of water is invalidated. Although the disqualification of drawn water is a Rabbinic decree, our Sages explained it based on an association found in a Biblical verse. Leviticus, op. cit., states: "Only a spring, a cistern, or a gathering of water shall be pure." Based on a comparison of the terms used in the verse, they explained: The water of "a spring" is not dependent on man's activity at all. The water of "a cistern" is entirely dependent on man's activity, for it contains drawn water entirely. Our Sages said: The "gathering of water" should not be entirely made up of drawn water like a cistern, nor need it come entirely from the hand of heaven. Instead, if it came into being partially through human effort, it is acceptable.
📖 Law vs. Rabbinic Decree
Scripturally, any collected water sufficient to cover a person's body is valid. Rabbinically, drawn water (water that was placed in a vessel) is invalid for a mikveh. If even three lugin of drawn water fall into a mikveh lacking 40 se'ah of valid water, the entire mikveh is disqualified.
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When Rainwater Collected in Containers Is Acceptable
What is implied? When a person places barrels on top of a roof to dry, but it rained and they became filled with water, even though it is during the rainy season, he may break the barrels or turn them over and the water collected from them is acceptable for immersion. Even though all of this water had been contained in vessels, the mikveh is acceptable, because the person did not fill it up by hand. Therefore if he lifted up the barrels and overturned them, all of the water in them is considered as drawn.
When a person places containers under a drainage pipe at any time and any season, both small containers and large containers, even containers of stone and the like that are not susceptible to ritual impurity, if they became filled with rainwater, the water is not acceptable for a mikveh. Even if he turned them over or broke them, the water collected from them is considered as drawn in every respect. For the containers were filled as a result of his intent, since it can be assumed that a drainpipe will conduct water. Even if one forgot containers under a drainpipe, the water is unacceptable for a mikveh. Our Sages issued a decree against one who forgot, lest a person place them there intentionally. Similarly, if one placed containers in a courtyard when the sky was densely cloudy and they became filled with rainwater afterwards, the water inside of them is unacceptable for a mikveh, since they were filled as a result of his intent. Moreover, our Sages issued a decree against one who forgot containers in a courtyard, lest a person place them there intentionally. If one placed containers in a courtyard when the clouds were dispersed and then the sky became cloudy and the containers became filled with rainwater, the water is acceptable for a mikveh, like that in containers left on top of a roof to dry. Similarly, when one left containers in a courtyard when the sky was densely cloudy, the clouds dispersed, and then became dense again and the containers became filled with rainwater, the water is acceptable. If he breaks the containers or turns them over, the water collected from them is acceptable for a mikveh.
When one who applies lime forgot a large container in a mikveh and it became full with water, even if only a small quantity of water remained in the mikveh and the majority of the water of the mikveh is in the container, he may break the container in its place. Thus the entire mikveh will be acceptable. Similarly, when one arranged containers in a mikveh to seal them and they became filled with water, even though the mikveh absorbed its water and no water remained except the water in the containers, one may break the containers. The water that collects from them forms an acceptable mikveh.
🌧️ Rain and Containers
Rainwater that falls into barrels set out to dry is not drawn water if it rained unexpectedly; one may break or overturn the barrels to release the water. Placing containers under a drainage pipe always renders the water drawn. A plasterer's container accidentally left in a mikveh that fills — the water is acceptable even if most of the mikveh water is now inside the container.
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How Three Lugin of Drawn Water Disqualify a Mikveh
How do three lugim of drawn water invalidate a mikveh? If there were less than 40 se'ah of acceptable water in a mikveh and three lugim of water fell in, making the entire amount 40 se'ah, all of the water is disqualified for use. If, however, there are 40 se'ah of water that was not drawn in a mikveh and then one drew water with a pitcher and poured it into the mikveh throughout the entire day, it is acceptable. Furthermore, when there are two mikveot, one above the other, and the upper mikveh had 40 se'ah of acceptable water and one was drawing water by hand and pouring it into that mikveh until the amount of water increased to the extent that 40 se'ah overflowed and descended into the lower mikveh, the lower mikveh is acceptable.
When a mikveh contained exactly 40 se'ah and one added a se'ah of drawn water and then removed a se'ah of water from it, the mikveh is acceptable. Similarly, if he added a se'ah of drawn water and removed a se'ah of water from the mikveh, the mikveh is acceptable provided the greater portion of the original water remained.
Drawn water does not disqualify the water of a mikveh when three lugin fall in unless they fall into the mikveh from a container. If, by contrast, the drawn water flows on the ground outside the mikveh and continues streaming until it descends into the mikveh, it does not disqualify the mikveh unless it constitutes half or more of the original 40 seah of water. If, however, the majority of the original 40 se'ah of water was acceptable, the mikveh is acceptable. What is implied? When a mikveh contains a little bit more than 20 se'ah of acceptable water, one drew water and poured it outside the mikveh, and then the water flowed and descended into the mikveh, it is acceptable, even if it reached a total of 1000 se'ah. This applies whether the water flowed on the ground or through a conduit or the like that does not disqualify a mikveh. The rationale is that drawn water that was caused to flow is acceptable if the majority of 40 se'ah water is acceptable. Similarly, if there was a little more than 20 se'ah of rainwater on an enclosed roof and one drew water by hand and poured less than 20 se'ah of water into the water, the entire quantity is unacceptable. Nevertheless, if one opened the drainage pipe and caused all the water to flow into one place, it constitutes an acceptable mikveh. The rationale is that when an entire quantity of drawn water was caused to flow, it is acceptable, provided the majority of the water was acceptable.
📏 The Three-Lugin Rule
Three lugin of drawn water disqualify only a mikveh with less than 40 se'ah of acceptable water. If a mikveh has exactly 40 se'ah and drawn water is added then removed, the mikveh remains valid. Drawn water disqualifies only when it falls directly from a container into the mikveh — water flowing along the ground does not disqualify.
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Mixed Rainwater and Drawn Water — Flow and Proportionality
Some of the scholars of the west ruled that since the Sages declared "An entire quantity of drawn water that was caused to flow is pure," it is not necessary that the majority of the water be acceptable. Instead, the perspective that required both a majority of acceptable water and that it be caused to flow are the words of only one Sage and they were already rebutted, for the conclusion of the passage states: "An entire quantity of drawn water that was caused to flow is pure." According to the words of the scholars of the west, if one would fill a container with water and pour it out and the water would flow to one place where it collects, it would be an acceptable mikveh. Similarly, all the pools in our bathhouses would be kosher mikveot, for all the water they contain was drawn and then flowed through pipes. Never have we seen anyone who performed such a deed, i.e., ruling that such pools are acceptable for immersion.
The following laws apply when rainwater and drawn water were mixed together in a courtyard and flowed into a cavity or they were mixed together on the steps leading to an underground cavern and then descended into the cavern. If the majority of the water was acceptable, the mikveh is acceptable. If the majority of the water was unacceptable, it is unacceptable. When does the above apply? When they became mixed together before they reached the mikveh, but instead, flowed and descended together. If, however, the acceptable water and the unacceptable water were descending directly into the mikveh, different rules apply. If it is known that 40 se'ah of acceptable water fell into the mikveh before three lugim of drawn water, the mikveh is acceptable. If not, it is unacceptable.
🌊 Rainwater Mixed with Drawn
Western scholars ruled that causing drawn water to flow on the ground purifies it, so a mikveh need not have a majority of valid water if the flow purified the drawn water. When rainwater and drawn water mix in a courtyard and flow into a cavity together, the majority of the water determines acceptability.
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🎓 Key Principles
Chapter 4
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Rabbinic Stringency on Drawn Water While Scriptural law requires only 40 se'ah of any collected water, the Rabbis added that water manually drawn and placed in vessels disqualifies a mikveh.
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Three Lugin: The Critical Threshold Three lugin of drawn water falling into a mikveh with less than 40 se'ah of valid water disqualifies the entire pool — this is the key Rabbinic measure.
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Intent and Placement Determine 'Drawn' Status Water that enters containers placed to catch rain is drawn water; water that enters containers accidentally or without intent may retain acceptable status.
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Flow Purifies — The Rule of Running Water Drawn water that flows along the ground before entering a mikveh does not disqualify it; the Rabbis of the west extended this to reduce the majority-valid-water requirement.