Mikvaot

Niddah and Zavah

1. A mikveh is effective to purify a niddah, zavah, and baal keri but a zav specifically needs to dip in a mayan.

Mikveh’s Minimum Measurements

1. A mikveh requires 40 seah at a minimum. The size of 40 seah is measured by 1 amah x 1 amah x 3 amot. A person who goes to the mikveh needs to go in it completely at one time and be completely covered by the water at one time.
2. The minimal amount of a mikveh theoretically is 332 liters but the practice is to use double or triple that amount.
3. A person who is large and can’t fit in a mikveh of 40 seah needs to dip in a larger mivkeh.
4. A mikveh that has 40 seah and is flat but a person can lie down in it and be covered by water at one time is a kosher mikveh.
5. There needs to be 40 seah the entire time one goes in the mikveh but if as one goes into a mikveh some water spills out and there’s less than 40 seah then the mikveh is unfit.
6. Mud can count for a mikveh if it is so thin that a cow would drink it. Some say that this can simply be determined by experimenting with a cow. Some say that there is a fixed measure and chazal established that as a stringency it would be need to be so thin that if a straw would be placed on top of it it would fall in. It is possible to dip in the thin mud in the mikveh as long as there is water covering the mud.
7. Any creature that grows in the water such as fish can count towards the mikveh if it is liquified.

Doubt if there was 40 seah

1. A kosher mikveh with 40 seah, which many people used and then was measured and there was 40 seah afterwards there is no doubt that it was kosher the entire time and there’s no concern that it decreased to less than 40 seah and was refilled. Nonetheless, it is proper to check that it has 40 seah before using it. If it is known that it naturally decreased to less than 40 seah at some points it is a concern and is only kosher if it was checked before being used.
2. A kosher mikveh with 40 seah, which after many people used was measure to be less than 40 seah is invalid and anyone who dipping in it at a time when it wasn’t known if it had 40 seah has to go to the mikveh again.

Water out of the Mikveh Counting to Mikveh

1. If two people go in a mikveh that was exactly 40 seah only the dipping of the first person is valid since once the drops of water on the body of the first person exit the mikveh the mikveh is incomplete. However, if the first person is still standing in the mikveh and then the second person dips according to some rishonim the second person’s dipping was effective. The halacha is that it isn’t.
2. A thick cloth dipped in a mikveh as long as it is partially touching the mikveh all of the water inside the cloth is considered connected. Once it is removed from the mikveh the water in it is considered sheuvim.

Holes and Pits Near the Miveh

1. Any small hole near the mikveh pit is considered part of the mikveh and connected if there is a hole the size of two fingerbreadths in diameter between the hole and the mikveh.
2. A crevice very close to a mikveh which would naturally fill up with water when the mikveh is filled up with water is considered part of the mikveh if there’s a hole of any size connecting that crevice with the mikveh. It is possible to be dip a vessel in that crevice.
3. A crevice very close to a mikveh with a wall between it and the mikveh, if it doesn’t naturally fill up with water when the mikveh is full, if the wall is so thin that it would collapse if a person would dip in it that crevice is considered part of the mikveh. Nonetheless it needs to have a reviyit in order to dip a vessel inside it. However, if that wall is sturdy and could stand up on its own the crevice is considered connected only if there’s a hole between the crevice and the mikveh the size of two fingerbreadths in diameter.

Splashing to Extend the Mikveh

1. If a person is in a mikveh and splashes water out of a mikveh to cover a vessel that’s sitting near a mikveh if that water remains connected to the mikveh that vessel is considered dipping in the mikveh. However, if that splash disconnects from the mikveh before the vessel is submerged the dipping of the vessel is invalid unless there is 40 seah in the splash alone.

Mayan’s Minimum Measurements

1. A mayan is different than a mikveh in that it purifies utensils even with the smallest amount and can also purify when it is moving. For a person who is going to purify themselves in a mayan it requires 40 seah just like a mikveh but the water of a mayan can still be moving.
2. If a mayan was less than 40 seah and more drawn water was added some say that it is in fact invalid since a mayan needs 40 seah for a person to go in it and since its requisite amount was completed with drawn water it is invalid. Others hold that it is kosher.
3. A mayan which has a majority of drawn water only is effective to purify someone if it is stationary and not moving.
4. A mayan which has a majority of rainwater is only effective to purify someone if it is stationary.

Zochlin

1. Only a mayan purifies whether the water is moving or stationary, but a mikveh is biblically invalid if the water is moving.
2. What is considered if the water is moving? Some held that it is considered moving even if it isn’t recognizable. Some held that it isn’t considered moving even if there’s movement but the entire mikveh is gushing like a spring. The majority opinion is that it is considered moving only if it is recognizably moving. A minor leak which drains the mikveh slowly but isn’t noticeable by looking at the water surface is permitted and the mikveh is valid.

Zochlin with water going into the mikveh

1. If water is flowing into a mikveh but water isn’t flowing out there’s a dispute whether that is considered zochlin.

Zochlin from Mikveh to Mikveh

Packet 11

Zochlin that isn’t recognizable

1. If there’s a tiny crack in the mikveh if the water draining is so minimal that it isn’t noticeable the mikveh is still fit. There are some poskim who are more strict and invalidate a mikveh with any drainage. On the other hand, there are those who are more lenient and would allow a leaky mikveh as long as it isn’t completely moving like a spring. This opinion is not accepted by the poskim.

Zochlin above 40 seah

1. If there’s a crack in the mikveh and the crack is above the point where the walls would contain 40 seah anyway, some rishonim hold it is valid, while others don’t. Ashkenazim are strict.

Zochlin because of a person dipping

1. Water which splashed out of a mikveh and bounces off the walls and is going to return to the mikveh isn’t considered zochlin since it is only caused by a person and is going to return.
2. If when a woman goes into a mikveh some of the water splashes out even if there’s more than 40 seah left in the mikveh some say that the mikveh is unfit since it is zochlin while others say that it is fit.

Zochlin because of a filter

1. Some say that if the filter in the mikveh was running when a woman went in the mikveh it is unfit since it is considered zochlin and others held it is fit. With regards to the question of sheuvim, it depends on whether the filter is a kli. It depends on the actual type of filter.

Katafras

1. Some define katafras as moving water.
2. A river isn’t considered katarfras.
3. Ideally the hashaka hole should be straight. If the hashaka hole is slanted vertically it is nonetheless valid.
4. The water on the steps are connected to the water in the mikveh even if it isn’t 40 seah. According to those who think that the stairs aren’t connected with the mikveh one should avoid having the hashaka hole on the stairs.

Spring Water Disconnected from the Spring

1. Water that was dribbling down a mountain is considered like a mikveh and not a spring unless it flows continuously.
2. Water that was dribbling down a mountain and was drawn together so that it should flow using a cane or anything else that is susceptible to tumah is invalid for a mikveh.
3. If a mikveh is created with something that is susceptible to tumah even rabbinic tumah is considered invalid as a mikveh.

Spring Water that Stopped Moved or Was Interrupted

1. A spring that flowed into a mikveh, whether it was filled up originally or not, is considered like a spring.
2. If the water streaming from a spring was interrupted it isn’t considered like a spring instead it is like a mikveh and invalid if it is moving.
3. If drawn water was added to a spring it is valid even if there is a majority of spring water. However, if there is a majority of spring water it is only fit while it is still and not moving.

Spring Flooded with Rainwater

1. If in a mayan there is a majority of rainwater compared to the springwater it is unfit if it is moving.
2. There is a dispute if a majority of rainwater invalidates a spring if that rainwater was added directly into the original pit of the spring. One should strict about such a case.

Rivers

1. A person shouldn’t go to the mikveh in a river. If there’s no mikveh available there’s what to rely on to go to the mikveh in a river. Before a person relies on such a leniency they need to consult with their rabbi.

Oceans

1. All oceans are like a mayan to dip in them even where they are moving.
2. One may not dip or immerse utensils for tevilat kelim in the tip of a wave but one may do so in the wave that broke and reconnected. Some say that the wave only purifies if there’s 40 seah in it. If the wave detached from the sea and is still moving it is invalid for dipping or immersing utensils in.

Sheuvim

Deoritta or Derabbanan

1. If the entirety of the mikveh or a majority of it is sheuvim (drawn water) it is invalid. Some poskim hold that it is biblically invalid and others hold that it is only rabbinically invalid.
   1. Some rishonim think that it is biblically invalid if it is filled up with water that was drawn with a kli that are susceptible to tumah or a person's kli that is susceptible to tumah and only rabbinically invalid if it is filled up with water that was drawn in a kli that isn’t susceptible to tumah.
   2. Some rishonim think that if it was filled up intentionally a person it is biblically invalid, but if it was filled in kelim by themselves it is only invalid rabbinically.
2. Ashkenazim hold that it is a biblical invalidation, while Sephardim hold it is only rabbinic.

Intention

1. Water in a vessel is only considered drawn if it was gathered in the vessel intentionally.
2. Water that entered a vessel without the owner realizing isn’t considered sheuvim. If a person left a vessel under a gutter to collect water when it was cloudy then the water collected in the vessel is sheuvim. If the vessel is placed there when it is sunny or when it was cloudy but afterwards the clouds cleared and then it rained, the water insider isn’t sheuvim.
3. When drawing water out of a mikveh and there’s a concern that some of the water will fall back into the mikveh as one is drawing out the water such that 3 lug of drawn water might fall into the mikveh that is lacking and invalidate it. In such a case unless all of the water is removed, if there’s 3 lug of water left it would invalidate the mikveh made on top of it. To avoid this concern one can either draw out the water with a vessel that has a hole of any size such that it couldn’t hold water or empty the mikveh and make sure it is dry before refilling it.
4. According to most poskim, there’s no concern when drawing out water from a spring which isn’t susceptible to the invalidation of sheuvim. However, some are concerned for that and as such require using a vessel that has a hole and can’t hold water or to empty the mikveh completely until it is dry before refilling it. Ashkenazim are strict about this question.
5. If there’s a receptacle in the pipe it isn’t considered filled in unless there is a permanent addition to the pipe.
6. If rainwater collected in jugs that were placed on the roof to dry the water inside can be used for a mikveh if the jugs are broken in their spot or pushed over. If they are picked up to pour them out the water is invalid.
7. If a container that held cement was placed in a pit for construction and forgotten there and rainwater collected inside it can be broken in its spot and the water isn’t sheuvim. If they are picked up or pushed over the water is sheuvim.
8. If porous jugs were placed in a pit with water in it in order that the walls of the jugs become cleansed and water entered into the jugs they can be broken but not pushed over.

What is a Vessel for Sheuvim

1. A vessel of any size can create sheuvim even if it is larger than 40 seah./
2. A vessel of any material that can hold water is considered a vessel to create sheuvim, whether or not that material would be susceptible to tumah.
3. A flat board which has no rim or has a partial rim but couldn’t hold any water at all wouldn’t create sheuvim which water that passed over it.
4. If a vessel is in a position in which it can’t contain any water even though if it were sitting normally it would hold water doesn’t create shuevim.
5. Shingles on the roof aren’t considered vessel to create shuevim since they weren’t made to hold water.
6. When dipping a pillow in the mikveh it would make the water sheuvim once it is picked up out of the mikveh.

1. If a vessel couldn’t hold water on its own but would hold water if propped up by other things it wouldn’t create sheuvim. - see bet yosef 201:34 it is kosher

Pipes

1. Pipes that have no receptacle don’t create sheuvim.
2. Pipes which have a receptacle of any size create sheuvim and invalidate a mikveh.
3. Pipes which didn’t have any receptacle when it was detached from the ground and after it was attached a receptacle is created is valid, but if the receptacle is created before it is attached it is invalid.
4. Pipes which widen and thin out in order to manipulate the water pressure and speed don’t invalidate the mikveh as the receptacle wasn’t made to hold water.
5. A bent pipe that could hold water is valid. There is a minority opinion that it is invalid. Some say that it is invalid only the angle created is less than 90 degrees and water could be held in that bend, however a bent pipe that is 90 degrees or more and just directs the water flow doesn’t create sheuvim. Others explain that according to the strict opinion any bent pipe is an issue even to direct water flow. A possible solution is to have one pipe flow into another pipe at an angle but not actually connect them and make them into one pipe.

Pipes Made to be Attached to the Ground

1. A vessel that was made to be attached to the ground is considered a vessel and makes the water sheuvim.

Vessel Attached to the Ground

1. If an unformed vessel was attached to the ground and then turned into a vessel that could hold water it doesn’t make the water it contains drawn (sheuvim).
2. If an vessel was able to hold water and then was attached to the ground it would make the water inside drawn (sheuvim).
3. A vessel that was punctured with a hole a diameter of two fingerbreadths and was attached to the ground is a valid mikveh. Even if the hole is then filled after it is attached to the ground it is still valid.

3 Lug of Drawn Water

1. If 3 lug fall into a mikveh that is lacking 40 seah it is invalid even if the mikveh is later split in two and rainwater is added to one of them. Since the mikveh was completed with an invalidation it is as though all of the water is invalid.
2. If 1.5 lug fell into 20 seah of rainwater and another 1.5 fell into another 20 seah of rainwater and then these waters connect they are valid since the complete invalidation of 3 lug was never applicable to either one of them.
3. If a pit is full of drawn water it is only fixed to be used for a mikveh once enough rainwater enters so that according to our calculation there’s none of the original drawn water besides something minimal less than 3 lug. The way this is calculated is by the use of two methods: 1) whatever proportion of the mikveh is drawn water that is the proportion of it that exits, or 2) by assuming that all the water that exits the mikveh is half drawn water and half rainwater. We are strict for the stringencies of each method.
4. If a mikveh less than 40 seah is invalidated with 3 lug of drawn water it can be fixed by having a bit more than 40 seah of rainwater enter and that amount exit. Some say that this is only effective if the rainwater exits by overflowing and not if it is drawn out.
5. If a mikveh that is invalid mixes completely with a mikveh that is valid they are both considered valid.
6. If less than 3 lug of drawn water fall into a mikveh that is lacking 40 seah the mikveh is nonetheless invalid until the more rainwater is added to complete the 40 seah and the drawn water doesn’t contribute to the measure of 40 seah. It doesn’t matter whether the drawn water is added in the beginning or at the end as long as the mikveh is lacking 40 seah.

Which Water Invalidates the Mikveh

1. Three lug of drawn water only invalidates the mikveh if it is a complete 3 lug or more and it looks like water. Less than 3 lug of drawn water together with some milk that fell into a lacking mikveh doesn’t invalid it. Water mixed with red wine that looks like wine doesn’t invalidate the lacking mikveh even if more than 3 lug entered.
2. Colored water invalidates a mikveh if there is 3 lugin of drawn colored water added to a incomplete mikveh.

Sheuvim for a Mayan

1. A spring that has drawn water added and the drawn water is in the majority it is only valid as a mikveh and not if it is moving. Some say that this is only if the drawn water was added to a still spring but if it was added to a moving spring the spring is still considered a spring, however, the halacha is strict in all cases to consider the spring with a majority drawn water to be like a mikveh.
2. If there was less than 40 seah in mayan and water added and then removed and made into mikveh is it kosher.

Sheuvim for a Mikveh

1. A pit that was filled up with rainwater but it wasn’t 40 seah and nearby there were three small holes filled up with drawn water and then the water from the pit subsumes the drawn water in the holes. If it is known that the pit had 40 seah of rainwater before the drawn was added it is fit. If not, it is invalid.

Sheuvim without a Vessel, Drawn by a Person

1. See the Tefisat_Yedey_Adam page.

If the Status of a Mikveh Is in Question Because of Sheuvim

1. If there’s a doubt if the water became sheuvim the mikveh is kosher. According to Ashkenazim it is only kosher if the doubt is whether 3 lugim entered it but not if the question is whether it is completely made of sheuvim.
2. If a person saw that a mikveh was empty and later came back and it was full he can assume that it was filled up with rainwater because most people involved with making mikvaot are experts.
3. If there’s two mikvaot each of which with less than 40 seah and 3 lugim of sheuvim fell into one of them and one doesn't know which one it fell into, they are both invalid. If the mikveh was then completed with rainwater so that it had 40 seah, one shouldn’t go into the mikveh but after the fact if one did one can rely on the fact that it was kosher.
4. If there’s two mikvaot each of which with less than 40 seah and 3 lugim of sheuvim fell into one of them and one does know which one it fell into, and then another 3 lugim of sheuvim falls into one of them, one can assume that it fell into the invalid one and the other is kosher after you add rainwater so that it has 40 seah of rainwater.
5. If there’s two mikvaot each of which with less than 40 seah and 3 lugim of sheuvim fell into one of them and one doesn’t know which one it fell into, and then another 3 lugim of sheuvim falls into one of them and one does know which one it fell into, one can’t assume that the second set of sheuvim fell into the same one that the first 3 lugim fell into and therefore both are invalid.
6. If there were two mikvaot one with more than 40 seah and one with less than 40 seah and 3 lugim of sheuvim fell into one of them, and one doesn't know which one it fell into, they are both valid after adding more rainwater so that they both certainly have more than 40 seah of rainwater.
7. If there were two mikvaot one which was invalid with sheuvim and one which was valid but lacking and 3 lugim fell into one of them one can assume it fell into the invalid one and the valid one is kosher after more rainwater is added so that it has 40 seah.
8. If there’s rainwater which flowed into a mikveh and there’s a doubt if it went through a vessel next to the mikveh before entering the mikveh it is invalid unless there was majority of a kosher mikveh in the mikveh to begin with.

Tefisat Yadey Adam Grama

1. The main discussion of Tefisat Yedey Adam is on its own page.
2. If the water was drawn into a mikveh using an indirect or delayed reaction according to some poskim it is valid as it wasn’t drawn by a person directly, while according to other it is invalid since it created artificially and not naturally. See Igrot Moshe YD 120:5 and Minchat Yitzchak 3:39:20.

Natan Seah Vnatal Seah

1. If a complete mikveh has drawn water put in and removed consecutively such that a majority of 40 seah of the original water was removed according to some rishonim it is completely valid, while according to others it is invalid. We are strict to avoid this but in extenuating circumstances if there’s no other mikveh available we can lenient.
2. Some say that the issue of natan seah vnatal seah is solved by having water flow into the mikveh and flow out since it isn’t similar to drawing water out with a vessel. Other disagree.
3. Some say that the issue of natan seah vnatal seah is solved by having water move along the ground for 3 tefachim before it enters the mikveh.

Snow and Ice

1. Snow or ice that was carried in a vessel or pipe isn’t considered drawn water after it melts. However, because some rishonim are strict one shouldn’t create a mikveh initially from tap water that was frozen and melted.
2. In extenuating circumstances it is possible to create a mikveh by freezing tap water, placing it in a mikveh, and having it melt. This should not be relied upon without consulting a great posek.
3. Using an ice machine to create ice is a discussion in the poskim.
4. Moving snow with something that is susceptible to tumah isn’t an issue.

Hamshacha

1. A mikveh that has 20 seah and a bit of rainwater and the rest of the mikveh is filled up with drawn water that was drawn along the ground is kosher.
2. A mikveh that was made completely with drawn water that was drawn along the ground according to a minority opinion is kosher but that opinion isn’t accepted and therefore, such a mikveh is invalid.
3. If drawn water mixes into a majority of rainwater and there’s hamshacha afterwards the mikveh is valid.
4. Hamshacha needs to be the length of 3 tefachim.
5. According to Ashkenazim, hamshacha needs to be on ground that could absorb water. According to Sephardim it isn’t necessary.
6. Whether hamshacha must be done on top of dirt or can be done on top of a kli attached to the ground is a dispute.
7. Cement absorbs water and is fit for hamshacha.
8. A spring that filled up a mikveh and during the summer it dried out, if a nearby pit is filled up with water and that water drained into the ground and the spring is filled up with that water from the pit the spring can be used as a kosher mikveh.

Hashaka

1. It is possible to validate an entire pit of drawn water by connecting with a mikveh momentarily, however, some say that the connection needs to remain open for the drawn water to remain fit.
2. According to some poskim one can’t add sheuvim water to a mikveh which has 40 seah but is very shallow so that a person couldn’t go to the mikveh in it. According to these poskim until the mikveh is fit to dip in one shouldn’t add sheuvim.

Size of Hashaka Hole

1. According to Ashkenazim, the connection has to be a hole that has a diameter of 2 fingerbreadths, while according to Sephardim a hole of any size would suffice.

Hashaka with Sheuvim

1. In order to create a connection between a mikveh and a pit of drawn water and validate all of the water, the hole connecting the two needs to be the size of a shifoferet hanod. The shifoferet hanod is two fingerbeadths turned in a circle.
2. The shifoferet hanod hole is only effective if it is complete full of water.
3. If the hole might be the size of a shifoferet hanod but it is unclear it is an invalid connection between mikvaot.
4. If there’s something blocking the transference of water stuck in the hole it is invalid.
5. A lot of small holes don’t add up to be one hole that would connect mikvaot.

A Momentary Hashaka

1. A momentary hashaka according to most poskim is enough to validate the drawn water. However, because there are some who disagree it is preferable to be strict.

Hashaka with Zochlin

1. Igrot Moshe YD 1:113 writes that if a mikveh is kosher and moving it is still possible to have a connection to a kosher mikveh to permit it. Even though a moving mikveh isn’t fit for tevilah it is a kosher mikveh to permit another mikveh. His proof is from the Rash Mikvaot 3:3 who says that if rainwater is coming into a mikveh and there’s water pouring out of the mikveh that is an acceptable way to validate the mikveh. Bet Yosef 201:20 and Shach 201:55 cite this. However, Shaarei Mikvaot 201:96 is strict based on the Maharit 2:18. Mishneh Halachot 10:156 is strict. He quotes Maharam Shik 198 who is also strict.
2. Chazon Ish (Tinanya 8:1) holds that a zochlin mikveh is invalid and cannot create hashaka to purify sheuvim. His proof is from the concept of mey tamsiyot shelo pasku. He understands from Raavad that it requires a reviyit to be kosher and therefore it needs the status of a mikveh which is stationary for hashaka to be operative. Chazon Ish 3 is strict and suggests either having the zeriya hole above where the water enters or having a plug.
3. Chelkat Yakov 111 is strict but it isn’t an issue if a little water at the end comes while it is moving since a majority of mikveh was already kosher with standing zeriya.

Hashaka between Shuevim or Mey Geshamim and a Mayan

1. The Mishna clearly states that a mayan which has a majority of sheuvim water is treated like a mikveh that it can only purify while standing still (eshborin). The Raah is bothered why this is the case if hashaka works to purify sheuvim water to become non-sheuvim in a mikveh. He answers that in fact hashaka is relevant to convert sheuvim water into mayan water to purify even will moving (zochlin). He explains that the Mishna means that in the place where the mayan flowed originally it is still a mayan, but in the places where it expanded or went further than before the sheuvim was added it is treated as a mikveh. However, the rest of the rishonim firmly disagree with this view and do not accept hashaka of sheuvim with a mayan.
2. Several explanations are provided why hashaka doesn't work here:
   1. Ritva explains that hashaka with sheuvim only works since sheuvim is really rabbinic even if there's a majority of sheuvim the mikveh is still kosher from the Torah. Since it is rabbinic the rabbis allowed added a lot of sheuvim to a complete mikveh even if the result will be that there is more sheuvim than mikveh water. However, zochlin is a Torah invalidation of mikveh water and so it can't be fixed with hashaka.
   2. Trumat Hadeshen writes that the reason hashaka works for sheuvim is because sheuvim is only invalid since it is detached from the ground. Hashaka reattaches to a mikveh and makes it like it is touching the ground. However, zochlin is a different invalidation that the Torah stated and for that hashaka doesn't help.
3. There is no distinction between sheuvim water and rain water for this discussion of hashaka with a mayan.
4. Does bitul of rov help to purify sheuvim water in a mayan? Several rishonim hold that bitul is helpful to allow sheuvim water or rain water in a mayan to become acceptable like mayan water. Within these rishonim they argue whether it is possible to have kama kama batel, consecutive bitul of a little bit at a time. Some rishonim hold that it is batel a little at a time and others hold it isn't.

Hashaka with Mikveh that doesn’t have 40 seah

1. If there’s drawn water next to a mikveh that is lacking 40 seah and the drawn water is connected with a small hole that doesn’t invalidate the mikveh because that drawn water is merely touching the mikveh and not mixed in it. The hole has to be small enough that from the hole to the opposite wall the amount of water that would be contained in such a cylinder or box is less than 3 lug. If the hole was the size that opposing it is 3 lug of water then the drawn water invalidates the mikveh. If the mikveh has 40 seah it is kosher.
2. If there was drawn water in the middle of a lacking mikveh it would invalidate the mikveh.

Placement of Hashaka Hole

1. The hashaka hole should be placed high enough that below it there is 40 seah in the rainwater mikveh.

Hashaka of Different Types of Water

1. Some say that one can’t do hashaka of a rainwater mikveh to a spring.
2. Hashaka to ice according to some poskim is valid.

Tevilah in and on a Kli

1. One may not go to mikveh in a kli and that is invalid biblically.
2. Biblically one may not dip in a vessel.
3. A moving mikveh on the back of a truck is questionable.

A vessel attached to the ground with and without a hole

1. If the vessel attached to the ground and is connected to a mikveh or mayan through a hole that has a diameter of two fingerbreadths it is biblically considered connected to the mikveh or mayan but nonetheless rabbinically one may not dip in such a vessel.
2. If there’s water going into a vessel it is invalid to be used for tevilah and the water that dribbles out of the vessel is also invalid.
3. If there’s a vessel that can contain 3 lug that’s built into the floor of the mikveh in the middle it invalidates the mikveh since it is seen as though all of the water above the vessel is contained in the vessel and drawn water invalidates a mikveh. However, if the vessel is build into the side of the mikveh it is kosher since the drawn water in the vessel merely touches the mikveh and doesn’t invalidate it. This is only invalid if the mikveh has less than 40 seah.
4. If there’s a vessel built into the bottom of the mikveh used to keep in all of the water in the mikveh and if it is drained there will be no more water in the mikveh then it is invalid even if there’s 40 seah since it is all drawn water.
5. Even a kli larger than 40 seah is invalid to be used to hold the water of the mikveh.
6. If there’s a vessel which has a hole of two fingerbreadths and through it there’s a connection to a spring and there’s water exiting the vessel, the vessel is invalid as a mikveh and the water that exiting the vessel is also invalid.
7. If there’s a vessel with a rim which water from a spring is flowing into and also out of all of the water is fit as a spring since the water on the rim connects the water in the vessel with the water in the vessel and makes it valid.
8. A person can immerse a vessel inside another vessel even if the outer vessel has a mouth smaller than a two fingerbreadth diameter as long as the immersion is effective for both the inner and outer vessel. In this case the immersion is only effective if the outer vessel mouth’s is vertical and not horizontal. However, if the immersion is only effective for the inner vessel then it is only effective if the mouth of the outer vessel has a two fingerbreadth diameter.
9. If the outer vessel is obligated in tevilat kelim rabbinically and the inner one biblically then the inner vessel isn’t considered as though it had tevilah unless the opening of the mouth is two fingerbreadths in diameter.
10. A person can immerse inside of a bag that is porous.
11. In theory a woman may immerse while wearing her clothing if they are loose. In an extenuating circumstance she may immerse while wearing socks and shoes.

Punctured on the Bottom

1. If a vessel is punctured on the bottom, according to some rishonim even if it has a tiny hole it isn’t considered a vessel and doesn’t create drawn water. The poskim don’t accept this opinion. If can hold even a little bit of water it is a vessel and invalid.
2. If a vessel is punctured on the bottom, according to most opinions if the hole has the diameter of two fingerbreadths it isn’t a vessel and doesn’t create drawn water. This is accepted by the halacha. However, some rishonim explain that even though such a vessel isn’t considered a vessel for drawn water it is still considered a vessel such that one may not immerse in it. Many rishonim disagree and the halacha follows their lenient opinion. If can hold even a little bit of water it is a vessel and invalid.
   1. If the vessel attached to the ground and is punctured by a hole on the bottom of the mikveh with a hole that has a diameter of two fingerbreadths, whether that hole was made before or after the vessel was attached to the ground, then it can be used for a mikveh. It isn’t a vessel to create drawn water and also one may even dip in such a vessel since it isn’t considered a vessel once it has a hole and is attached to the ground.
3. If a vessel is punctured on the bottom, according to all opinions if the hole has a diameter of a pomegranate it isn’t a vessel and doesn’t create drawn water. Additionally, all agree that a person can immerse in such a vessel. If can hold even a little bit of water it is a vessel and invalid.

A Vessel Floating in the Mikveh

1. A vessel not attached to the ground floating in the mikveh doesn’t invalidate it and the water inside it isn’t considered drawn water.
2. A sponge which was filled up with 3 lug of drawn water or a bottle with a small opening and it was filled with 3 lug of water if that sponge or bottle fall into a mikveh which is lacking 40 seah, they don’t invalidate it since the water is inside them isn’t connected to the mikveh. If the water were to be squeezed out of the sponge or spilled out of the bottle it would invalidate the mikveh.
3. If there is a clothing partially in the mikveh and a person squeezes water out of it into the mikveh it is considered drawn water to invalidate a mikveh with 3 lug. Some say that this is only the case if it is completely picked up out of the mikveh, while others say it is even if it is partially out of the water.

On the Back of Vessels

1. If water flows over the back of vessels the water is valid as a mikveh, meaning that it is valid when it is 40 seah and stopped. However, one may not immerse on top of any type of vessels.
2. If part of the water is flowing over an inverted vessel and part of it isn’t and they are all connected then all of the water is valid as a spring.

A vessel created before or after it was attached to the ground

1. A pipe that was chiseled out and then attached to the ground is invalid for a mikveh unless a hole on the bottom with a diameter of two fingerbreadths is made in it.
2. A stone or cement that was attached to the ground and then chiseled out to be used as a pipe or vessel isn't considered a vessel and doesn’t create drawn water. Some say that one may even dip in such a vessel while others hold that one may not actually dip in such a vessel.

A vessel inside the mikveh

1. If the vessel is inside of a mikveh or mayan some rishonim say that one may dip in such a mikveh or mayan but the halacha is that one may not dip in such of a mikveh or mayan rabbinically.
2. If the vessel is inside of a mikveh or mayan and has a hole that has a diameter of two fingerbreadths some rishonim say that it is fit to go inside of that vessel that is surrounded by water on all sides but the halacha is that it is ineffective.
3. One may not go to mikveh standing on top of a kli.

A Colored Mikveh

1. A mikveh whose water changed colors from the original look of the water even if it doesn’t look like wine or another liquid is invalid. There is a dispute whether this invalidation is rabbinic or biblical.
2. A colored mikveh is invalid even if the color changes after it has 40 seah.
3. A colored mikveh can be fixed by having it connected to a spring.
4. A colored mikveh can be fixed by having more water added to it to change its color back to regular water. If the mikveh has 40 seah the water added can even be drawn water.
5. A spring isn’t susceptible to the invalidation of having its water change colors.
6. If part of the mikveh changed colors that area doesn’t count towards the mikveh but if there’s 40 seah that is unchanged it is a kosher mikveh if one dips in the area that didn’t change colors.
7. A mikveh that changed colors on its own is valid.
8. A colored mikveh is only invalid if the actual coloring agent is added to the mikveh such as wine or dye, but not if it is only colored because of something else such as colored or dirty water.
9. A mikveh that was incomplete and wine was added so that the color of all of it changed then even if drawn water is then added it isn’t invalidated because of drawn water because while it is invalid as a colored mikveh being drawn doesn’t invalidate it. Afterwards if more water is added such that the whole mikveh returns to the original color it is fit.
10. Some poskim hold that a mikveh that is incomplete and invalidated because 3 lug or more of drawn water was added can be fixed as follows: wine is added so that the entire mikveh changes the look of wine, then more water is added until its original color returns. However, many poskim hold that this isn’t solution doesn’t work. Even the lenient opinion can be relied upon if the original invalidation was only rabbinic and not biblical.
11. It is permitted to add chlorine powder to a complete mikveh if it doesn’t change its color.

Creation of a Mikveh through Something Susceptible to Tumah

1. A mikveh may not be created by the use of something that is susceptible to tumah otherwise it is invalid. This invalidation is biblical.
2. If the mikveh that was created with something that is susceptible to tumah and is invalid is connected to a mayan it is fixed and made valid again.
3. A flat wooden board without edges that is used to direct water into a mikveh if the water would have flowed that way anyway it is valid, if not, some poskim say it is valid and others hold it is invalid. The poskim are only strict if the wooden board was used to service people and utensils such as a tray, table, and bed board.

If the water would have reached the mikveh anyway

1. If the mikveh is created with something that is susceptible to tumah but the water would have flowed that way anyway to create the mikveh, the mikveh is valid.
2. If the water flows over something that is susceptible to tumah but the water afterwards flows over wood, dirt, or something that isn’t susceptible to tumah at all the resultant mikveh is kosher. Some say that this is only true if the water would have flowed into the mikveh without the vessel that is susceptible to tumah.

Stopping Water from Exiting

1. If a vessel that is susceptible to tumah is used to plug up a hole in the mikveh the entire mikveh is invalid because without that plug the mikveh would be invalid as the water would flow up and having the plug there is considered creating a mikveh with something that is susceptible to tumah.
2. If a vessel that is susceptible to tumah is used to repair a mikveh when the mikveh is completely valid but without the repair there is a concern it will later become invalid, the mikveh is valid.

If Water is Attached to the Mikveh or Spring

1. If the water flows over something that is susceptible to tumah the water is invalid for a mikveh, however, if the water is attached to a complete mikveh or a spring, some rishonim hold it is valid but others hold it is still invalid.

Indirectly using something that is susceptible to tumah

1. Using a vessel which is susceptible to tumah even if it is only indirectly holding the water is a problem.

Connecting Pits of Water that Overflow

1. If there are three pits of twenty seah each, the middle one filled with drawn water and the others rainwater, and three people dip in these pits so that they overflow and connect, they are just as unfit as they were beforehand.
2. If there are three pits of twenty seah each, one side one filled with drawn water and the others rainwater, and three people dip in these pits so that they overflow and connect, they are all considered fit since they combine together when the people went inside and the two pits of rainwater connected. Practically, each pit of twenty seah isn’t fit until another twenty seah is added because a complete mikveh is forty seah.
3. If there are two pits of twenty seah, one with drawn water, one with rainwater and they connect they remain as they were beforehand.

A Hole on top of a Hole

1. A mikveh on top of a mikveh if there is a hole the size of two fingerbreadths in diameter is considered connected.
2. There are three pits on a slope, the with twenty seah, the bottom with twenty seah, and the middle with forty seah. If there is water streaming between them, according to some rishonim we say that the bottom one is connected with the middle one, while the halacha follows the rishonim who say that only the middle pit is valid.

A non-Jewish owned Mikveh

1. If a non-Jew owns a mikveh if you know that there was always at least 21 seah some say that you can be lenient to rely on the non-Jew who says that it was completed with rainwater. Many poskim hold that you can’t be lenient.

Assessing the Status of an Unknown Mikveh

1. If someone finds a man made pit of water in Israel outside of a city it is assumed to be rainwater and a kosher mikveh, but in the Diaspora it is assumed to be a non-kosher mikveh. Nowadays the assumption that it is a kosher mikveh doesn't even apply in Israel.
2. If you know that a natural pit filled with water such as in a field it is assumed to be rainwater and is a valid mikveh.

Building a Mikveh so it isn’t a vessel

1. Reinforced concrete with metal rods in the cement is a discussion in the poskim if it is acceptable.
2. It is permitted to make a mikveh with stones that are attached to the ground isn’t considered a vessel even though the complete mikveh could hold water.
3. Making a mikveh with cement is acceptable. Even though it is appears to be one unit after it dries as though it was a vessel, it is considered building a structure and not creating a vessel. Also, the cement frame can’t be lifted up as a unit like a vessel.
4. A complete vessel such as a bathtub which was a vessel before it was attached to the ground is an invalid mikveh.
5. A mikveh made of pre-made cement slabs, one per wall and one for the floor, is questionable.
6. Some mikvaot are made by starting with a cement floor. Then a cement piece with four walls and a divider is placed on top of the floor to establish the mikveh with a hashaka mikveh. Some poskim are weary of using such a mikveh, while others are lenient.

Going to a hot mikveh

1. Theoretically, Sephardim hold that a mikveh should be cold and if hot water is added it is invalid. However, Ashkenazim are lenient to permit a hot mikveh. Today the minhag of all communities is to be lenient. It is permitted to have a radiator in the walls of the mikveh heat up the water since it is clear how it is being heated.
2. There is no issue of going to mikveh in the hot springs of Tevariya even though they are hot.
3. Going to a warm mikveh Friday night, Sephardim advise going ben hashemashot, while Ashkenazim advise going at night itself.

Showering after going to the mikveh

1. Ashkenazim hold that the women shouldn't bathe or shower immediately after going to the mikveh. Sephardim are lenient.
2. How long does the prohibition apply according to Ashkenazim? Some say it is for an entire day until the next night. Some are lenient once she came home and touched her husband. Some allow once he gets home even if they didn't touch.
3. The minhag of not bathing or showering after going to mikveh doesn't apply to a man going to mikveh for keri. A baal keri can go in a mikveh of 40 seah of drawn water.

How to do Tevilat Kelim

1. You can dip a large vessel in a mikveh that is just 40 seah specifically by doing the following: put it in the mikveh upside down, turn it over in the mikveh, turn it over again and remove it upside down. The reason it needs to be put in upside down is so that the water of the mikveh isn’t displaced and spilled out of the mikveh. The reason it needs to be removed upside down is so that the water isn’t removed from the mikveh making it less than 40 seah.

Procedure and Position for Dipping in the Mikveh

1. A person shouldn’t dip in a mikveh that the water is so deep or so shallow. Instead it should be filled to the point that it is a half amah above the belly of a person.
2. If is shallower than that if there’s no other available options a person can dip in such a mikveh by lying down horizontally but not by bending over so much. Bending over would cause a person to have unnatural folds and pockets which would be considered an interposition between the body and the water. Some permit going to the mikveh lying down even initially.
3. A mikveh with water that is spread out and can’t be used for dipping in its current state it is permissible to put down wood so that the water congregates on one side of the mikveh.
4. If a person needed to go to the mikveh and doesn’t know if they went to mikveh or whether they completely submerged or whether the mikveh had 40 seah he must go to the mikveh again since his tameh status remains until he surely went to the mikveh.
5. It is possible to dip in a stream of water from a spring if one completely submerges themselves in it.
6. If a person jumps into a mikveh with a lot of water that will contain more than 40 seah even after water splashes out the dipping is valid.
7. Some say that a person shouldn’t dip in the mikveh twice, one is sufficient and doing it twice will make a person more likely not to take each one seriously. Others defend the practice of dipping twice.

Trust regarding the status of a Mikveh

1. An individual is trusted regarding the status of the mikveh if it is in his hands to fix it.

Modern Mikvaot

1. Chatom Sofer 214 holds that the best way to make a mikveh is to use zeriya. The benefit is that hashaka with sheuvim is questionable (Tosfot Rid and Kesef Mishna) and zeriya is firmly established. Another positive is that there’s no question of fulfilling the opinion of Rabbenu Yerucham to have continuous hashaka. The downside of such an approach is natan seah vnatal seah (Rambam and Raavad against Rash and Rosh) and that is solved since there’s no obvious act of taking away water (Ramban, Bet Yosef). The Divrei Chaim disputes this point and shows that the Raavad would invalidate the mikveh because of natan seah vnatal seah even if it isn’t evident. Chazon Ish held you should just do zeriya.
   1. Maharshag YD 65 defends Chatom Sofer about problems of natan seah vnatal seah. He suggests doing zeriya into pit two and spill over into tevilah pit then hashaka once with pristine hashaka bor. He says that the issue of natan seah doesn’t apply to the tevilah bor since the drawn water was added to the other pit and only overflowed there.
   2. Mishna Halachot 10:146 said that zeriya in second pit is only effective if it is first still and then spilled over. Cheshev Sofer YD 13 said that was the minhag to do.
   3. Satmer Rav in Divrei Yoel 69 said you can do zeriya with bor al gabi bor and have it overflow into bor tevilah. Mishna Halachot 10:146 said it is pasul since the katafras makes it not connected to a mikveh and zochlin is invalid for zeriya so both mikvehs become invalid.
   4. Igrot Moshe YD 2:94 writes that you shouldn’t just do pour zeriya because of natan seah vnatal seah.
2. Divrei Chaim responsa CM 1:37 holds that the best way to make a mikveh is to use hashaka. The downside is that to fulfill Rabbenu Yerucham we need the hashaka pit always open and to avoid natan seah vnatal seah we need to refill the rainwater pit frequently so that there remains a pristine minimum of 21 seah of rainwater. Being that the longer the hole between the mikveh’s is open the more water that is transferred the sooner the rainwater needs to be changed. The solution is that the hole should be opened only once to create the hashaka and then close it up. That isn’t concerned for the Rabbenu Yerucham but it is concerned for the Rambam and Raavad of natan seah vnatal seah. Igrot Moshe YD 2:94 approves of this type of mikveh since momentary hashaka works for natan seah vnatal seah. However, the Tzemech Tzedek 171 argues that this doesn’t actually solve the Rambam and Raavad either because they certainly would accept Rabbenu Yerucham as they fundamentally need the presence of 21 seah. [Problematically the Divrei Chaim 201:20 himself makes the same point as the Tzemech Tzedek.] Because of this point, Rabbi Moshe Bick (Taharat Yom Tov 8:27) convinced the Satmer rebbe to hold like the Chabad mikveh.
   1. 3 mikvaot. One to connect one time and one to keep open. Mishna Halachot 10:146 that’s the minhag of Ungar and Galisiya like divrei chayim with 3 pits. He answered the Tzemech Tzedek by saying that although the Raavad would agree with Rabbenu Yerucham that’s only for a mikveh made completely with drawn water but not for a mikveh that is just invalid because of natan seah vnatal seah. That can be fixed with a momentary hashaka. Maharshag 1:66 also rejected the Tzemech Tzedek’s equation. Igrot Moshe YD 2:94 would agree.
   2. Divrei Yatziv YD 117 agrees that the minhag is to have 3 pits, one open all the time and one opened only momentarily.
3. The Satmer Rav in Divrei Yoel 69 had another solution. He held you can have a bor hashaka with a divider. It is a bor al gabi bor min hasad. It is a continuous connection between the bor tevilah and bor hashaka but there’s a third mikveh below and isn’t getting contaminated quickly. Chesed Yehoshua 2:57 agreed.
   1. Chelkat Yakov held to do this with a tiny connection. Since the issue is only rabbinic then the hole doesn’t need to be a shifoferet hanod. That would mitigate the issue of natan seah vnatal seah. Teshuvot Vehanhagot didn’t like it because of zochlin. Shevet Halevi thought it isn’t zochlin.
   2. Tzelemer Rav in Gedulot Merkachim YD 52 disapproved of the Satmer mikveh since it was katafras of the Divrei Chayim. It can be fixed if the top area independently has 40 seah. Mishna Halachot 10:146 s.v. haamnam quotes the Kloizenberger Rebbe who also disapproved of the bor al gabi bor min hasad because of katafras. In s.v. vdaah he writes that the bor al gabi bor on the side is invalid even if the top area has 40 seah since it is katafras and you can’t do any hashaka with katafras. Shevet Halevi says this is wrong because standing katafras isn’t pasul in hashaka. That’s a combination of wrong definitions.
4. Rashab (Pitchai Mikvaot 9:23 p. 327 cites the notes of the Rashab printed at the end of Shulchan Aruch Harav) holds that the best way to make a mikveh is to use a bor al gabi bor. The benefit is that it fulfills Rabbenu Yerucham and also natan seah vnatal seah because the transference of the water between the lower and upper mikveh is minimal. The Divrei Chaim 1:46 argued that the hashaka was invalid since it is considered katafras. Others argued that this was an incorrect explanation of katafras. Satmer Rebbe (packet 15 p24, Taharat Yom Tov 8:27) agrees with the Rashab that it is the best solution and having a hashaka bor is unnecessary. In practice the Satmer prefer bor al gabi bor min hasad (Divrei Yoel YD 80).
   1. Imrei Yoshar 2:79 and Rav Moshe (Igrot Moshe YD 3:65) held that katafras is only with a pipe in which the water is moving and not two pits one on top of the other. Divrei Chayim 1:46 himself held it was an issue.
   2. The Pitchei Mikvaot p. 327 quotes the Klozenberger that a mikveh on top of a mikveh is kosher if there’s also a hashaka on the side. He cites the Betzel Chachma who says that it wouldn’t help since once it is katafras you can’t connect to it but the Pitchei Mikvaot didn’t understand how having an extra hashaka could possibly ruin the mikvah. Minchat Yitzchak 6:90 questions such a mikveh. Rav Moshe Feinstein (Mesorat Moshe v. 2 p. 228) said that if there are some lubavitch in the area it is best to make a bor al gabi bor with another bor hashaka on the side to satisfy everyone. He said that he didn’t believe that anyone who invalidate it.
   3. Vishnitzer Rebbe held that the best mikveh is one that made with rainwater and isn’t changed except once a year. Packet 15 last pg nytimes