• March 24, 2023

What are the Fundamental Halachos of Mikvah?

Klal Yisroel’s holiness and purity depend in big part on tevilah in a mikvah, both of people and dishes. This was certainly the case in the times of the Beis HaMikdash, when many halachos regarding tumah and taharah were more applicable. Thus, we saw a valuable benefit in explaining to the public multiple halachos and principles about the kashrus of a mikvah in a manner that can appeal to everyone, even those who are not involved in the kashrus of mikva’os. To this end, we will בעזהשי”ת discuss in the coming issues the halachos of mikva’os and what makes them kosher or pasul in order to spread vital knowledge, concepts, and halachos in Klal Yisroel.

Mikvah, Maayan

Water “Bidei Shomayim”

  1. The posuk says (ויקרא י”א, ל”ו), “אך מעיין ובור מקוה מים יהיה טהור.” Chazal say based on this (תו”כ), “Just as a spring is ‘bidei Shomayim,’ so too a mikvah must be bidei Shomayim.” In other words, a precondition for mikvah water and the common denominator between a spring and a mikvah is that the water cannot be manually drawn. It must collect “bidei Shomayim,” i.e., on its own (שו”ע יו”ד סי’ ר”א ס”ג). There are three types of water that are kosher for tevilah, as will be explained (par. 4 and on).
  2. Kashering drawn water through hashakah. One way to enable the use of drawn water is through a principle called hashakah (below, 19). For example, say there is a cistern of rainwater next to another cistern of drawn water. If the cisterns are connected with an open space as wide as the opening of a leather bottle [“שפופרת הנאד”] through which water can pass, then the posul water becomes kosher through hashakah. Someone/something that is immersed in the drawn water is then considered to have been immersed in the rainwater (שו”ע שם סנ”ב).
  3. Size of שפופרת הנאד. “שפופרת הנאד” refers to the width of the tube that used to go into the opening of leather drinking pouches. It is a space wide enough for the two fingers next to the thumb to easily rotate inside (שו”ע סעיף מ’). In modern terms, this is about 5-6 cm (מו”ר הגרי”י בלויא בפתחי מקוואות פ”ט אות ד’ הע’ י’).

Types of Water

  • Mayim chayim. “Mayim chayim” is water from groundwater springs or from rivers that extend from springs that is still in its natural location. Only a zav needs tevilah in mayim chayim to become tahor (רמב”ם פ”א מקוואות ה”ה, פ”ט ה”ח). Also, the water to purify a metzora or for the parah adumah ashes to purify someone who is tamei meis must be mayim chayim, as the posuk says (חקת י”ט, י”ז), “ונתן עליו מים חיים אל כלי’.” Seawater is not mayim chayim. People with other types of tumah may also toivel in water that comes from a spring, in seawater, or in a mikvah.
  • Maayan. A maayan is water that comes from the ground or a river, including impaired or salty water. This water can be metaher even when it is flowing [זוחלין]. The sea is considered a “maayan” in the sense that it is metaher when flowing. Maayanos and seas are kosher for all tevilos except the ones mentioned above.
  • Mikvah. A rainwater mikvah is a cistern where 40 sa’ah of rainwater collected without human involvement. The collected water must be standing, not running – this is referred to as “ashboren” (שו”ע שם ס”ב).

In Earlier Generations

  • To introduce the halachos of mikva’os, it is worthwhile to give some background on how mikva’os have evolved to the form we use today.
  • In a spring. A long time ago, most Yidden relied on rivers, springs, or cisterns properly connected to a spring with hashakah for tevilah. The advantage to this was that the water was flowing and did not become polluted like standing water. They also avoided concerns of “nasan sa’ah v’natal sa’ah” [to be explained next issue], which do not exist for springs.
  • However, this came along with many difficulties. First of all, not every place has a river or spring. Also, a riverbank is an open area. Furthermore, spring water is very cold, especially in the winter and in cold climates. It was not possible to heat the water due to the natural flow of water in a spring.
  • Barrel in a river. In those days, some gave the following option for tevilah in hot water connected to a spring: take a large barrel that could contain 40 sa’ah of water; make a שפופרת הנאד-sized hole to remove its status of a vessel; lower it into a spring with metal chains; seal the hole with a stopper; pour hot water into the barrel.
  • But the water in the barrel is drawn. Thus, when they would go into the barrel for tevilah, they would remove the stopper to connect the water in the barrel to the spring water through hashakah. They would then close the hole right away to prevent the water from getting cold. This heter was built on the concept of “קבעו ואח”כ חקקו,” which is mutar (ע”פ הש”ך סי’ ר”א סקכ”א).
  • However, many Acharonim questioned this method for multiple reasons. Two examples: “קבעו ולבסוף חקקו” does not work for tevilah in a vessel, which is posul d’oraisa (נודב”י יו”ד ח”ב סי’ קמ”ב, שו”ת רע”א סי’ ל”ט, פת”ח סק”ז ועוד); and hanging by chains is not considered connected to the ground (שו”ת חת”ס, שו”ת אמרי א”ש סי’ ע”ח).
  • Later, they came up with a working solution. A pomegranate-sized hole was made in the bottom of the barrel and then permanently sealed with cement and pebbles in such a way that it would not have the status of a vessel even after it was sealed. Next, a second, שפופרת הנאד-sized hole was made to kasher the drawn water in the barrel through hashakah, and a stopper was inserted. The stopper was opened every time someone went in for tevilah. It could then be put right back into the hole to prevent the water from getting cold (שו”ת מאיר נתיבים סי’ י”א, שו”ת בית אפרים סי’ נ”ג, שו”ת חת”ס סי’ ר”ו, לחם ושמלה סקמ”ד).

In Recent Generations

  1. Mikvah. After some time, more recent poskim began to prefer kashering water for tevilah with a 40-sa’ah mikvah of rainwater, making it easy to heat the water. The Acharonim saw to it that this would be done in the best possible way, without any concerns. This remains the primary method of preparing a mikvah to this day, with added chumros and strategies to make it kosher according to all opinions without any issues.
  2. At first, this method was also hard to keep. Standing water quickly becomes polluted and dirty, and there is’nt always enough rain to replenish the water. But this problem could be fixed by kashering drawn water, i.e., by making a tevilah mikvah of drawn water next to a cistern of rainwater, which kashers the drawn water through hashakah. Then, when the tevilah water becomes dirty, it could be drained and refilled with new drawn water that becomes kosher through hashakah with the adjacent cistern of rainwater.
  3. However, this also came with challenges. Back then, there was not running water in every house. Water had to be drawn with buckets from a spring or well and transferred to the tevilah mikvah, a task involving much effort and exertion.
  4. With the subsequent advent of running water in every house, rainwater cisterns again became the most common and convenient solution for regular use. This was especially so after the discovery of electricity, which aided in pumping out water, making it easy to change the water in the tevilah mikvah. All mikva’os today are made with rainwater.

Bor Hashakah, Bor Zeriah

  1. There are two main ways to make drawn water kosher for tevilah: hashakah and zeriah, as will be explained. In earlier times, some people only used one method, but today, usually both methods are used together. Since each one has pros and cons, using both gets the advantages of both, as will be explained.

Bor Hashakah

  1. The root of “hashakah” means to kiss, as the two types of water are connected and “kiss” each other (רש”י חולין דף כ”ו ע”ב ד”ה משהחמיץ, גלות עליות פ”ו מ”ח אות ג’). Some derive hashakah from the posuk (ויקרא י”א, ל”ו), “אך מעין ובור מקוה מים יהיה טהור” (תורת כהנים שמיני פ”י פרשתא ט’, סמ”ג עשין רמ”ח, שו”ת הרא”ש כלל ל”א).
  2. A bor hashakah is structured as follows: next to the tevilah mikvah, another mikvah is made to receive at least 40 sa’ah of rainwater; this mikvah is called the “bor hashakah.” A hole is made high enough in the wall separating the two mikva’os that there can still be 40 sa’ah of water beneath it. The tevilah mikvah is filled with tap water from the city supply – which has the status of drawn water – until above the hole so that the drawn water in the tevilah mikvah becomes kosher by being connected to the rainwater through the hashakah hole [see image, taken from the wonderful sefer “מקוה מים” by Rav Yirmiyahu Katz, with permission; many thanks to him]
  3. Now, the rainwater can remain fresh and clean for a long time in the bor hashakah, while regular usage happens in the tevilah mikvah, where the water can easily be changed.

Constant or Momentary Hashakah?

  • The poskim argue whether it is enough to effect hashakah for the waters to touch once, after which the drawn water is permanently kosher even though there is a stopper separating the waters; or whether constant hashakah is needed for a kosher tevilah. Strictly speaking, we hold one moment of hashakah is enough to make the water permanently kosher (שו”ע סנ”ב). However, some say that if the hole is sealed with a stopper, the water reverts to its state of pesul (רבינו ירוחם הובא בש”ך ס”ק קי”ב).
  • Since the poskim argue, many Acharonim were machmir to keep the hole open at the time of tevilah, especially for a d’oraisa tevilah (גידולי טהרה בשו”ת סי’ י’, שו”ת בית שלמה ח”ב יו”ד סי’ ס”ב בשם חת”ס, שו”ת ערוגת הבשם יו”ד סי’ קצ”ז).

Bor Zeriah

  • An bor zeriah [or otzar zeriah] is similar to a bor hashakah in the sense that posul water is fixed with kosher water, but the method is slightly different. A bor zeriah is made next to the tevilah mikvah and filled with 40 sa’ah of rainwater, and a hole is made in the wall between the bor zeriah and the tevilah mikvah [usually above the water level in the tevilah mikvah]. Then, tap water from the city supply is used, not to fill the tevilah mikvah as is done in the hashakah method, but to fill the bor zeriah until the water rises and flows through the hole into the tevilah mikvah.
  • Before kashering drawn water in a bor zeriah, the tevilah mikvah must be completely empty of any water. This is because three log of drawn water invalidates a mikvah if it was present before 40 sa’ah of kosher water (שו”ע סט”ו). Then, the tevilah mikvah is filled by pouring drawn water into the bor zeriah, where it is “planted” and becomes kosher and tahor. When the water level in the bor zeriah reaches the hole in the wall, the water flows into the tevilah mikvah.

Pros and Cons

  • With a bor hashakah, a mikvah worker must ensure that the water in the tevilah mikvah reached and filled the hashakah hole. Otherwise, the water in the tevilah mikvah was never kosher (ס’ שאול שאל סי’ קכ”ה אות ו’, ליקוטי הערות על שו”ת חת”ס יו”ד סי’ רי”ב אות ד’). To satisfy the opinions that require constant hashakah (above, 23), one must also ensure that the hole between the boros is open during tevilos. This is not a concern with a bor zeriah since all the water in the tevilah mikvah is kosher; there is no need to ensure that it stays kosher.
  • Bor hashakah water mixing with tevilah water. Some are also concerned about water from the bor hashakah mixing with the tevilah water. There is a hygiene concern, as the standing water in the bor hashakah can become putrid and polluted over time and then mix with the water in the tevilah mikvah. There is also a halachic concern that after many tevilos, rainwater mixing with drawn water can create a problem of “nasan sa’ah v’natal sa’ah” (חזו”א יו”ד סי’ קכ”ג).
  • With a bor zeriah, there is a concern of “nasan sa’ah v’natal sa’ah” (ש”ך ס”ק ס”ג). Some poskim are also concerned about the ability of “flowing water” [זוחלין] to kasher drawn water that enters while it is flowing (שו”ת מהר”ם שיק יו”ד סי’ קצ”ח, שו”ת עמק שאלה יו”ד סי’ ס”ב). There is also the concern that the tevilah mikvah was not dry before it was filled, in which case there is an issue of three log of drawn water making the whole mikvah posul.

Bor hashakah and zeriah. Because of these concerns, the minhag is to set up a mikvah with a bor hashakah and zeriah so that it is kosher lechatchilah in the most effective way. This will be explained in the coming issue בעזהשי”ת.

Zerachya Shicker is the translator for the English version of חוקי חיים. The Chukai Chaim is a halacha sheet in a league of its own. Started in August 2016 (Av 5776), the Chukai Chaim currently has a readership in the tens of thousands across the globe.

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