Siman 160

The Rambam wrote in chapter 6 of Berakhot, law 7: "Four things disqualify the water: a change in appearance, being uncovered, performing labor with them, and spoilage that prevents an animal from drinking from them. How so? Water whose appearance has changed, whether in vessels or in the ground, whether due to something that fell into them or due to their location—these are disqualified. And so too, if they were uncovered with an uncovering that prohibits them from drinking—they are disqualified for netilat yadayim." Thus far his words. And behold, regarding uncovering, the Tur wrote that nowadays, since we are not concerned with uncovering, they are valid even for netila. Thus far his words. And in truth, the matter of uncovering is not known to us at all since snakes are not common among us, as is written in Yoreh Deah siman 116. And so too, that which he wrote: "whether in the ground," certainly his intention is regarding drawn water that is in the ground, and he follows his reasoning that we explained at the end of the previous siman, that drawn water in the ground, even when there are forty seah in them, one may not immerse the hands in them; for in a place where it is permitted to immerse the hands, a change in appearance does not disqualify, as a change in appearance does not disqualify in a complete mikveh, as is explained in Yoreh Deah siman 201 (Bach). Rather, he follows his reasoning, and we have already explained there that they disagree with him.

However, regarding that which he wrote: "with a change of appearance, whether due to something that fell into them or due to their location," even though in Mishnah Yadayim chapter 1 we only learned: "If ink, gum, or vitriol fell into them and their appearance changed—they are disqualified," see there, nevertheless, the Rambam holds that due to their location is like by means of something that fell into them, since the cause is not due to the essence of the water. And if they changed due to themselves, such as if they stood for many days and became green—the Rambam did not disqualify, for behold, even regarding the waters of purification we learned at the end of chapter 8 of Parah: "Water that changed and its change is due to itself—it is valid," and all the more so for the rabbinic washing of hands.

And according to this, the words of the Tur and the Shulchan Aruch in section 1 are very puzzling, as they wrote: "Water whose appearance has changed, whether due to itself, or due to something else that fell into it, or due to its location—is invalid." Thus far its words. And from where do we know to invalidate when they changed due to themselves? The commentators (the Taz, the Magen Avraham, and the Bach) have already raised this difficulty and ruled that they are valid; see there. And in my humble opinion, the primary view is like the Tur and the Shulchan Aruch, for it is known that water standing in a vessel for many days until its appearance changes to greenness, when one searches there, one will find many flies and worms, and through this its appearance changed. It turns out that the entire change is due to something else, but in the language of people, they call it "changed due to itself." And a proof for this matter is from the Mishnah in Parah there that we cited, that if they changed due to themselves they are valid, and at the beginning of the ninth chapter of Parah it is taught regarding a flask of mei chatat: "If sheratzim or creeping things fell into it and burst, or if its appearance changed—it is invalid." This shows that it is the way of water to change due to creeping things; if so, why was this not taught at the end of the eighth chapter? Rather, it is certain that there, where it deals with a spring, it is not their way to change due to creeping things, as is known by the senses, but in a flask, it is the way of water to change because of them. And there is a further proof from Chullin (107a): for Rav Sheshet asked Amemar: Do you care about the appearance? He said to him: Yes; see there. And it is difficult: what kind of question is this? Is it not an explicit Mishnah in the first chapter of Yadayim as I have written? The Tosafot and the Rosh answered that regarding the Mishnah, one can say it deals with terumah; see there. And this is not understood at all, for all the laws there are for chullin. But according to the Tur and the Shulchan Aruch, it works out well and simply, for the Mishnah deals with a change due to something else: due to ink, gum, etc., as I have written, and he asked him about appearance due to itself, and he said to him that we care, and the reason is as I have written. Therefore, it appears to me for halachah and for practice like the Tur and the Shulchan Aruch, that even due to itself—it is invalid, for in truth this is not "due to itself," as I have written.

The performance of labor, how so? We learned in Yadayim there: "If one performed labor with them or soaked his bread in them—they are invalid; if one rinsed vessels with them or wiped measures with them—they are invalid. If one rinsed new or already rinsed vessels with them—they are valid." See there. We further learned there: "Water in which a baker dips rolls—is invalid; but when he rinses his hands in it—it is valid." See there. And this is the explanation: If one performed labor with them that was necessary for the labor, such as cooling liquids with them (the Rosh there), or soaking his bread, or rinsing vessels that require rinsing, or wiping measures where liquids had adhered, or dipping rolls—since all of these require this—it is called labor and it is like wastewater and invalid for netilat yadayim. But if one rinsed already rinsed or new vessels, where there is no need for the labor at all—they are valid, for this is not called labor. And the baker who rinsed his hands in them, even though he needs this, nevertheless, he took the water he needed from the vessel and with the remainder no labor was performed (the Rambam), and see in section 8.

If one soaked his bread in them, they are disqualified, even if he did not intend for this but rather the bread fell there and was soaked (Turei Zahav subsection 1), if he requires the soaking of the bread; and certainly if he intended to soak in this vessel and it fell into this vessel, they are disqualified. But if the bread fell and he immediately took it out of the water—they are fit (Magen Avraham subsection 4). And a baker who rinses his hands in the water, of which we said they are fit, this is when he scooped water from them in his handfuls to smear the surface of the loaves, or immersed his hands and smeared the surface of the loaves, for now the water he required he took, and the remainder in the vessel had no labor performed with them. But if he washed his hands in the water that is in the vessel—they are disqualified, for behold, he performed labor with all of them (Turei Zahav subsection 3). And there are some among the early authorities who permit even in such a case (Beit Yosef in the name of Sefer HaTerumah), and the reason is that he holds that this is not called labor at all, but such is not the approach of the Rambam and the Tur and the Shulchan Aruch (Turei Zahav ibid.). And so too if he rinsed vegetables in them—they are disqualified when he requires their rinsing, but if they were clean—they are fit (Magen Avraham subsection 5), as it is like clean vessels. However, if he soaked the vegetables in them so that they would not wither—it is certainly called labor and they are disqualified (ibid.). And the same law applies if he placed vessels in them during the summer days that had split and in the water they would contract—the water is disqualified (ibid.), but if he placed live fish in them so that they would not die—it is not called labor (ibid.), for the water does not act upon them at all but rather saves them from death, and even if they died there they are fit (Eliyah Rabbah subsection 6).

And know that our teacher, the Rema, wrote at the end of section 2, and this is his wording: "And the same law applies to water in which the baker rinses his hands from the dough stuck to his hands." Thus far his words. And according to the order of the matters, it refers to fitness; see there. But this is not according to the system of the Rambam, but rather according to the system of some of the Rishonim that we wrote of in the previous section, and in truth they disagreed with our teacher, the Rema, on this (Taz, subsection 4, and Yam Shel Shlomo, and Eliyah Rabbah). And furthermore, he should have written "and some say," for he explicitly disagrees with our teacher, the Beit Yosef, who wrote the reason that those remaining did not have work performed with them, see there, and consequently, by rinsing his hands within them, work has been performed with all of them and he needs the work. And it appears more likely to me that an error fell into the printing, and this gloss should be slightly earlier, upon that which our teacher, the Beit Yosef, wrote: "And if the baker dipped the loaves in them - they are invalid." Thus far his words. Upon this he says: "And the same law applies to water in which the baker rinses his hands etc.", meaning they are invalid, and so we maintain (and even though the difficulty of the Taz from the water before the blacksmith is not such a difficulty, see there, nevertheless the truth is that this is not according to the previous system).

It is stated in Gittin (53b) that there are vessels in which they make marks for the weight of meat, and they place water and meat in them, and when the water rises to this mark the weight is such, and when it rises to this mark the weight is such—it is called "performed work with them," see there. And there is one who wrote that if one placed into the water something for a pleasant fragrance, it is called "performed work with them" and they are disqualified (Magen Avraham subsection 5 in the name of Shelah), and it is a wondrous thing to disqualify for this, for the reason that if one performed work with them they are disqualified is because it is like wastewater, and here he intended to improve them through this and he did improve them, and furthermore there are proofs to validate them (see Magen Avraham there). Therefore, for the halacha, they are certainly valid (ibid.), and see the end of section 17.

And know that according to what has been explained regarding cooling liquids within the water—it is considered that a labor was performed with them and they are disqualified. And it is a wonder regarding the custom of the world, for they place bottles of beer or types of water into the vessel of water so that they do not become warm, and despite all this, they wash their hands from them. And it appears to me that they hold like that which one of the great authorities wrote, that cooling only disqualifies when one placed them in while hot so that they should cool in the water, but if one placed them in while cold so that they should not become warm—it is not considered that a labor was performed with them and they are valid (Eliyah Rabbah subsection 6 in the name of Olat Tamid and Dammeshek Eliezer, see there). And know that there is one who wrote that if one checked a vessel with water to see if it is whole or broken, the water is disqualified (Sha'arei Teshuvah in the name of Birkei Yosef), but in my humble opinion it is not so, for this is not a labor, as the vessel is made for water and he checked if it is fit or if it is not fit, and this is not an incidental labor.

Water that is before a blacksmith, even if its appearance has not changed, is invalid, because it is known that work was performed with it, namely, that he extinguished the hot iron in it. And water that is before a barber, which he uses while he cuts the hair of others—if its appearance has changed, it is invalid, and if not, it is valid. This is a Tosefta in Yadayim, and all the Rishonim cited it and did not explain what the barber does with the water. According to the context, it appears that he only takes a small amount of water in his cupped hands from the vessel, and therefore the remainder is valid as no work was performed with it, and it is like a baker who rinsed his hands at the end of section 4.

Water from which chickens drank or which a dog licked, there is one who is concerned to disqualify them based on that which we learned in a mishnah regarding mei chatat: that any bird that drank from them disqualifies the water except for a pigeon, because all birds raise their mouths and drops fall from their mouths into the water (Parah chapter 9, mishnah 3), and so we learned there: if a domestic animal or a wild animal drank from them - they are disqualified for this reason. And his words do not appear correct, for there they were not disqualified due to the reason of melakhah, as this is not melakhah, but rather because they are no longer "living waters into a vessel" (Tosafot Chullin 9b), and even if it were due to melakhah, these few drops were nullified within the water of the vessel (Taz subsection 5). Furthermore, shall we learn from all the stringencies that exist in mei chatat for netilat yadayim (Beit Yosef). Rather, the primary ruling is that the water is kosher regardless of who drank from it, whether a domestic animal, a wild animal, or birds. However, regarding the drinking of a dog or a pig, it is proper to be stringent, for the water has become repulsive and it is like wastewater (Magen Avraham subsection 7). And they brought this from the Tosefta (ibid.), but I did not find this in the Tosefta.

The Rambam wrote in chapter 11 of Mikvaot, law 9: "A vessel that contained a revit of water valid for netilat yadayim, and one placed into it a small amount of water invalid for netilat yadayim—behold, these are valid (for they were nullified by the majority). If one took from the vessel an amount equal to what he placed, and only a revit remained as it was—behold, this is invalid, because the invalid water completed the measure of the revit." Thus far his words. And he wrote this based on the sugya in Zevachim (22a), see there; and similarly Rashi explained there (s.v. 'l'ma'utei'), except that he wrote that this is only regarding an exact revit, for a small measure such as this is not considered significant enough to nullify them, see there. And he was forced to this, for if not so, it is a wondrous thing, for even regarding prohibited matters we say that once they are nullified they are nullified, and all the more so regarding netilat yadayim which is lenient as it is rabbinic. Therefore he explained that only regarding an exact revit is the law so, but when there was more than a revit and a small amount of invalid water fell there—they are nullified even if he took what he placed afterwards, and one can say the intention of the Rambam is also so. However, even regarding an exact revit the Tosafot wondered at this stringency, and they wrote (s.v. 'l'revit') that this was not stated regarding netilat yadayim but rather regarding the immersion of vessels, see there. And it appears that this is the opinion of all the poskim who did not bring this law at all, and even according to Rashi and the Rambam it is an uncommon matter that there should be an exact revit. Nevertheless, for the halacha we maintain that invalid water that was mixed with valid water less than half—is nullified and permitted for netilat yadayim, and it is simple that this is specifically when their appearance has not changed (see Beit Yosef in Bedek HaBayit and in Magen Avraham subsection 7, and examine carefully).

Work only invalidates with drawn water, whether it is in a vessel or in the ground in less than forty seah, but not with the water of a mikveh or a spring while they are still attached. There is one who wrote that only regarding the matter of work are a mikveh and a spring distinct from vessels, but regarding a change of appearance or if they became disqualified from the drinking of an animal, they are also disqualified in them (Taz, subsection 6). These are baffling words, for since they are valid for the immersion of the body, all the more so for netilat yadayim, and in Yoreh Deah siman 201 it was explained that these things do not disqualify in a complete mikveh, see there (the Pri Megadim also struggled with his words, see there).

Water heated by fire — one may wash the hands with them. And even though they are not fit for mayim acharonim, as will be explained in siman 181, this is because after eating the hands are full of filth and the hot water spreads it, as is written there; but for mayim rishonim it is permitted, even if the hand would be scalded by them. And there are those who forbid when the hand would be scalded by them, and in the Gemara (Chullin 107a) there are two versions regarding this. And all this is regarding water heated by fire, but with the hot springs of Tiberias, meaning hot water that descends from the mountains — one may not wash the hands with them, and the reason is because they are bitter and are not fit for the drinking of a dog. But if there should be found flowing spring water that is fit for the drinking of a dog — one may wash the hands with them, and therefore with sea water one may not wash the hands, for they are not fit for the drinking of a dog. However, there is one who wrote that when one boils them they become fit for the drinking of a dog and one may wash the hands with them (Magen Avraham subsection 12 in the name of the Radbaz), and indeed our teacher Yonah in the eighth chapter of Berakhot wrote that we require that a person be fit to drink them under duress, see there, and the Rambam in the sixth chapter wrote "the drinking of an animal," and regarding netilat yadayim, one who relies on the lenient opinion has not lost.

Therefore, one may immerse the hands in the hot springs of Tiberias when they contain forty seah, for they are not disqualified for the immersion of his body, and all the more so they are fit for the immersion of hands. However, to wash from them with a vessel—no, because they are not fit for drinking. Rashi in Chullin (106a) explained the reason: that when the sages instituted [the washing], they did not institute it with hot water, and these are worse than water heated by fire which had a period of fitness. Thus far his words. According to this, even if they are sweet water, it is forbidden to wash from them for netilat yadayim, and not as I wrote in the previous section. However, the Rambam and the Rashba and all the poskim wrote the reason is because they are not fit for drinking. And that which we wrote that forty seah are required for the immersion of the hands, this is when the spring is not in its place, for in its place one does not need forty seah, as a spring purifies with any amount. And that which requires forty seah is if one drew them on the ground via a trench outside of their place, and the trench is in the ground and he severed them from the flowing spring, for then forty seah are required. And even though in siman 159, section 35, we brought that some say even in a mikveh forty seah are not required, nevertheless, the hot springs of Tiberias are worse and everyone agrees that specifically forty seah are required (see Taz and see Magen Avraham, subsection 10). And even if this trench is connected to the hot flowing spring such that water is connected to water, nevertheless, Rashi and the Rashba hold that one may not immerse the hands in them when they do not have forty seah, because we decree lest he take them in a vessel. Our teacher Yonah disagrees with them and holds that forty seah are not required, since it is a spring. However, when there are forty seah in the trench, even according to Rashi and the Rashba one may immerse (Beit Yosef).

Therefore, salty or foul or bitter waters that a dog cannot drink from are invalid for netilat yadayim, even though they are valid as mikveh water for immersion. And turbid waters due to mud mixed into them—if a dog can drink from them, they are valid both for netilat yadayim and for a mikveh; and if it cannot drink from them, they are invalid for both, even for a mikveh. For this is worse than bitter waters, which still have the name "water" upon them, but that which is mixed with mud does not have the name "water" upon it. See in Yoreh Deah siman 201, where several laws were explained regarding this detail.

One may wash the hands with anything that was originally water, such as red worms if one crushed them until they became like water, and similarly fish oil when one crushed them, and snow, hail, frost, and ice—that is, water that congealed from the cold, which is called "ice." Our teacher, the Beit Yosef, wrote in section 12 that if one crushed them until they became water, one may wash with them and immerse in them if they have the required measure. Thus far his words. And it implies that without crushing them, one may not wash the hands with them. However, above in siman 159, section 37, we wrote that to immerse one's hands in a pile of snow of forty se'ah is certainly permitted. And it can be said that our teacher, the Beit Yosef, also holds this way, and that which he required crushing was specifically for washing over the hands or for immersion when there are not forty se'ah present. In Yoreh De'ah, siman 201, he wrote that in a time of pressing need, one may permit immersing his hands in forty se'ah of snow. Thus far his words in his great book there. Therefore, it can be said that here it is dealing with a case that is not a time of pressing need, and one should be lenient in the law as we wrote there (and so wrote the Magen Avraham in subsection 16).

Some say that netilat yadayim is only with water alone and not with other liquids or fruit juices, because they established netilat yadayim like the matter of tevilah, which is only in water alone, and so it is written: "and his hands he did not rinse in water." This is the opinion of the Ra'avad, and the Rosh also holds this in the seventh chapter of Berakhot (siman 31), and he brought proof that even water whose appearance has changed is invalid for netilat yadayim, certainly other liquids. The opinion of Rashi there (50b) is that one may perform netilat yadayim with fruit juices and other liquids. And one must distinguish between these and water whose appearance has changed, for in water they have changed from what they are, but these have not changed (see Tosafot there). The opinion of the Rashba is that even though from the perspective of netilat yadayim they are valid, nevertheless one should not perform netilat yadayim with wine, whether he added water to it or whether he did not add water to it, so as not to treat a significant thing like wine with contempt, as it changed for the better from the essence of the fruit until it establishes a blessing for itself, and therefore one should not do so ab initio. It also appears that with all liquids there is "bal tashchit," unless it is a time of pressing need when there is no water, he is permitted to perform netilat yadayim with fruit juices, and if he does not even have fruit juices and wine, he must of necessity perform netilat yadayim with them. And certainly it is permitted to perform netilat yadayim in a time of pressing need with beer or honey-water called mead, which are cooked and their essence is water. And one cannot say that if so, the appearance of the water has changed, for one can say that since it changed for improvement, we have no concern with it (Magen Avraham subsection 19, and his difficulty requires study for certainly there are three divisions, and examine this well). Some say that only with white wine is it permitted to perform netilat yadayim and not with red, but the majority of opinions tend to permit it (and what the Taz wrote in subsection 10, the Eliyah Rabbah in subsection 24 already refuted him).

And so it appears from the words of the Rambam in chapter 7 of Berakhot, law 9, where among the laws he wrote there regarding the prohibition of degrading food, he wrote: "And one may not wash their hands with wine, whether undiluted or diluted, and similarly one may not ruin other foods and drinks in a manner of degradation or kicking." Thus far his words. And this is certainly so, that to wash hands with liquids is a manner of degradation, for the Holy One, Blessed be He, created them to be drunk and not to be poured out, but from the essential law of netilat yadayim it is permitted. Therefore, if there is no water – it is permitted, for he does not do so because of degradation but because of necessity.

Every doubt regarding hands is pure, according to the law of a rabbinic doubt which is ruled leniently. Therefore, water regarding which one has a doubt whether labor was performed with it or not, or if one washed his hands and is in doubt whether there was the required measure—namely, a revi'it—or not, or whether they are impure or pure, or a doubt whether he washed his hands or not—we follow the lenient path. Nevertheless, there is one who says that even though from the essential law it is certainly so, nonetheless, if he has water, we say to him: "Arise and wash your hands without a blessing," so that you do not come to poverty (Levush). And this is when he has a doubt whether the primary washing was done properly, but when the primary washing was done properly and the doubt arose afterward whether his hands became impure or not, or if he is in doubt whether he had a lapse of concentration or not, or if he touched a place of filth or not, and similar cases—he does not need to return and wash even as a stringency, because we establish them upon their status quo (see Magen Avraham subsection 13, who wondered at this regarding the Yam Shel Shlomo, for a lapse of concentration disqualifies, see there. And his difficulty is perplexing, for there is a doubt regarding this itself whether he had a lapse of concentration, for if he certainly had a lapse of concentration, it is obvious that he must wash, as written in siman 164, see there and examine carefully).

Our teacher, the Rema, wrote in section 11: "One who did not wash his hands and touched water—those waters are not disqualified for washing and are not called impure water, but it is forbidden to wash his hands from water with which his fellow has already washed" Thus far his words. The explanation of his words: Even though in siman 162 it will be explained that if one washed one hand and it touched the other—it is impure, and if so, seemingly all the more so when he touched the water before washing. But it is not so, for only at the time of washing, when he purifies the hands, does impurity apply then according to the details that will be explained there; whereas before the washing, the rabbis did not decree, and as long as the water is in the vessel, it is not disqualified. And a proof for this is that it was explained in section 4 that when a baker rinses his hands in water, it is permitted to wash the hands from them, and this is an explicit Mishnah as written there, and the baker surely did not wash his hands for eating, and despite all this, the water is valid. Therefore, even one who exits the bathroom and dips his hands into a vessel of water, and took some water in his cupped hands and poured them out—the rest of the water in the vessel did not become impure (Yam Shel Shlomo), because this is before washing. However, if he did not take in his cupped hands but rather dipped his hands in the vessel and the water remained there, behold all the water became impure (Taz, subsection 9). And even though they are not for washing, nevertheless, ultimately they became impure at the time of their rinsing from the impurity of the bathroom, and it is like a washing (see Eliyah Rabbah, subsection 20, who is uncertain about this, nevertheless he did not decide to be lenient, see there). And this is what our teacher, the Rema, concludes: "But etc.", meaning that you should not say that just as before washing there is no impurity, so too after washing; for it is not so, as the washing water has already become impure, and how could they return to their fitness. And even if he washed with a lot of water, nevertheless the status of impurity is upon them and it is forbidden to wash with them once more (and that which he wrote that his fellow washed, he took the common case, and the same law applies to his own washing water, and it is simple).

We learned in a mishna at the beginning of tractate Yadayim: "A revi'it of water is given to the hands for one, even for two; from a half-log for three or for four; from a log for five, for ten, and for a hundred," meaning it teaches an exaggeration, and the intent is as long as there is enough water to pour on each one (Tur). And this is its explanation: The sages enacted that specifically from a revi'it of water one may wash for the hands, and with less than a revi'it it is nothing, and this is even for one. However, even for two a revi'it suffices when the first poured only half, for so the sages estimated that a half-revi'it is enough for the hands, and therefore the second washes with a half-revi'it, because these waters came from the remnants of purity (Chullin 107a). And behold, according to this measure, a revi'it and a half would have been enough for three, but since the men are many, we concern ourselves that perhaps they will not be precise to wash properly until the joint, and therefore they said a half-log. Nevertheless, ex post facto, if there is a revi'it and a half and the first washed with a half-revi'it—it will certainly be effective for two to have a revi'it, only if the first washed with more than a half-revi'it, the remainder will suffice only for one (Bartenura there).

However, there is a dispute regarding this, as some say they must all wash at once, and some say even one after the other. This is the wording of our teacher, the Beit Yosef, in section 13: "There must be a revi'it in the water, and these words apply to one person. But for two who come to wash as one—the latter does not require it, even one after the other, provided that the stream does not stop. How so: If there was a revi'it of water in the vessel, one extended his hands and another pours over his hands, and a second came and extended his hands below him near the hand of the first, and the stream descends upon the hand of the first and to the hand of the second which is below it—the hands of both are pure, even though the measure of the revi'it was diminished when they reach the hands of the second—his hands are pure, because they come from the remnants of purity." "And some permit even when they wash one after the other, since at the time one of them began to wash there was a revi'it in them, therefore they also count for the second because they come from the remnants of purity. And in this manner they wash from a chatzi log for three and for four, and from a log for several people, as long as the water suffices to pour three times on the hand of each one. And the same law applies that four and five people may place their hands side by side or one on top of the other and wash as one, provided that they loosen their hands in a manner that the water reaches each one" thus far his words. And all this is when they initially intended both to wash as one, but when initially one intended to wash for himself and afterwards the second also changed his mind and extended his hands below him—his hands are as impure as they were, and he must dry them and return and wash them (Magen Avraham, sub-section 20).

And know that the words of the Rambam in this matter are perplexing, for he wrote in chapter 6, law 10: "Four or five people may wash side by side or one above the other with a single pouring, provided they loosen their hands so that the water may reach them, and that there be in that pouring a revit for each and every one." Thus far his words. And it is perplexing in that he requires a revit for each one, contrary to the Mishnah. However, the Rambam follows his own reasoning in his commentary on the Mishnah and in his introduction there, that the first waters are not less than a revit for each and every one, and this Mishnah refers to the second waters, regarding which they were lenient. And this is only for terumah, but for chullin one does not need second waters at all, and therefore he omitted this law entirely here in the laws of blessings, and wrote this law in the laws of mikvaot chapter 11 regarding terumah; see there. And the Tur and the Shulchan Aruch did not cite his opinion at all, since he is a lone view in this interpretation, and one should not be stringent regarding netilat yadayim to be concerned for this stringency. Nevertheless, the common custom is according to his words, and two people do not wash from a single revit.

It is necessary that there be a revi'it gathered in one place and in one vessel, for if one washed from an eighth and then again washed from an eighth—his hands remain as impure as they were, and he is obligated to dry them and return and wash from a revi'it, for if he does not dry them the second washing will not be effective, as the water will become impure from the hands as written in siman 162. And the revi'it they spoke of applies whether to one who washes both his hands or to one who washes only one of his hands, and whether to the hands of a small child in stature or to the hands of an adult, for the sages did not differentiate. And if two people washed, this one his one hand and that one his one hand, and afterward the second person returned and washed his second hand—they are like three people, because his second hand is considered now like another person since he did not wash at the beginning but only his one hand. Therefore, if there was at the beginning a half-log in the vessel—his hands are pure, and if not—his second hand is not pure for the reason we wrote, that one does not wash with less than a half-log for three people for the reason that perhaps they will not be exact, as written in section 21, and there is no difference between one hand and two hands.