Please explain the rulings concerning the various types of water and the manner of purifying different kinds of impurities with them.

Please pay attention to the following points:

1. Water is the greatest material blessing from Allah and the source of the creation of living beings. Allah has made it the means of purification from impurities, saying: ﴿وَأَنْزَلْنَا مِنَ السَّمَاءِ مَاءً طَهُورًا﴾[1]; “And We sent down from the sky purifying water,” and: ﴿وَيُنَزِّلُ عَلَيْكُمْ مِنَ السَّمَاءِ مَاءً لِيُطَهِّرَكُمْ بِهِ وَيُذْهِبَ عَنْكُمْ رِجْزَ الشَّيْطَانِ﴾[2]; “And He sends down upon you water from the sky to purify you with it and to remove from you the defilement of Satan.” Therefore, anything that is called “water” in its absolute sense is a purifier—meaning it can be used to remove both physical impurity (khabath) and ritual impurity (hadath) and to prepare oneself for performing prayer. However, something that is not called “water” in its absolute sense, but only as part of a compound containing “water,” is actually not “water” and, at the very least, cannot be a purifier of ritual impurity—such as juice or water that, due to being heavily mixed with other substances, is no longer called “water” in its absolute sense. This is because Allah has commanded the performance of wuḍu and ghusl with “water,” saying: ﴿فَلَمْ تَجِدُوا مَاءً فَتَيَمَّمُوا صَعِيدًا طَيِّبًا﴾[3]; “Then if you do not find water (for wuḍu and ghusl), perform tayammum with pure soil.” Nonetheless, such water may still be a purifier of physical impurity, especially in cases where absolute water is not available; because in the purification of physical impurity—unlike ritual impurity—the intention of drawing near to Allah is not required, and the sole purpose is the removal of impurity, which can be achieved by anything pure. For example, the place of defecation can be purified by a stone, impure shoes by the ground, and impure objects by sunlight—although purifying them with water is preferable.

2. Water is categorized according to its natural movement into flowing water and stagnant water. Flowing water refers to water such as that of springs, qanats (underground water channels), streams, rain, and seas, which flows by its nature. Therefore, it does not retain impurity unless it is overpowered by it—that is, unless it takes on the color, smell, or taste of the impurity. Such water—whether in small or large quantities—is pure and, accordingly, a purifier as long as it has not taken on the color, smell, or taste of the impurity. As for stagnant water, it refers to water that does not flow by its nature and, accordingly, retains impurity. Therefore, it is not a purifier if impurity falls into it—unless the amount of water is large enough that the impurity is unlikely to reach all of it. In such a case, one can use the portions of the water where it is not known for certain that the impurity exists. In the view of Abu Hanifah, this amount is such that when one side of the water is moved, the other side does not move, since impurity—like the movement—does not reach all parts of the water in that case. In the view of Shafi‘i, it is “two qullahs,” based on a narration from the Messenger of Allah : «إِذا بَلَغَ الْماءُ قُلَّتَیْنِ لَمْ یَحْمِلِ الْخَبَثَ»[4]; “Whenever water reaches two qullahs, it does not carry impurity.” In the view of the Ahl al-Bayt, it is “one kurr”[5]. However, in the view of Mansoor Hashemi Khorasani , all three refer to the same amount; as one of our companions informed us, saying:

«قُلْتُ لِلْمَنْصُورِ: إِنَّ النَّاسَ رَوَوْا عَنْ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ أَنَّهُ قَالَ: إِذَا بَلَغَ الْمَاءُ قُلَّتَيْنِ لَمْ يَحْمِلِ الْخَبَثَ، قَالَ: صَدَقُوا، قُلْتُ: وَمَا الْقُلَّتَانِ؟ قَالَ: بِرْمِيلَانِ وَهُمَا قَدْرُ كُرٍّ مِنَ الْمَاءِ وَهُوَ مَاءٌ كَثِيرٌ لَا يَنْتَشِرُ فِيهِ الْخَبَثُ»; “I said to Mansoor: ‘People have narrated from the Messenger of Allah that he said: Whenever water reaches two qullahs, it does not carry impurity.’ He said: ‘They are right.’ I said: ‘What is two qullahs?’ He said: ‘Two barrels, and that is equal to one kurr of water, and that is a large amount of water, and impurity does not spread throughout it.’”

This means that, in the view of His Eminence Mansoor, each “qullah” is equivalent to one “barrel,” and each barrel has a capacity of between 100 and 200 liters. Accordingly, “two qullahs” or “one kurr” of water, in his view, equals 200 to 400 liters of water. This range includes the amounts mentioned among the Sunnis—204, 210, 217, 270, and 307 liters—and those mentioned among the Shia—377 and 384 liters. However, most common barrels, which are oil barrels, have a capacity of about 159 liters; therefore, the average amount of “two qullahs” or “one kurr” of water can be considered about 318 liters. Nevertheless, the truth is that the mention of this amount in the words of the Messenger of Allah and his Ahl al-Bayt, as well as in the words of Mansoor Hashemi Khorasani, has an advisory and approximate nature, not a binding and determinative one. This is because the non-spread of impurity in “kathir water” (i.e., water in a large quantity) is an objective and natural reality resulting from the abundance of water compared to the volume and type of impurity. Therefore, the statement of Sharia about it is a report of fact, not a legislative command. Based on this, the rule in this matter is that any water not entirely permeated by the impurity that has fallen into it is not impure. There is no fixed or precise amount for this; it can vary depending on the volume and type of impurity that has fallen into it, fluctuating between 200 and 400 liters, though it can be somewhat less or more. However, based on the ruling of intellect, its certain amount is water that does not entirely move when a part of it is moved; and based on the report of Sharia, its average amount is “two qullahs” or “one kurr”—equivalent to about 318 liters of water—which has been confirmed by well-known and widely transmitted narrations from the Prophet and his Ahl al-Bayt. This is derived from the statement of Mansoor Hashemi Khorasani , of which one of our companions informed us, saying:

«سَمِعْتُ الْمَنْصُورَ يَقُولُ: الْمَاءُ لَا يَنْجُسُ وَلَوْ كَانَ يَنْجُسُ لَمَا كَانَ يَطْهُرُ شَيْءٌ أَبَدًا، قُلْتُ: أَلَيْسَ الْمَاءُ الْقَلِيلُ يَنْجُسُ إِذَا لَقِيَ نَجَاسَةً؟! قَالَ: الْمَاءُ لَا يَنْجُسُ وَلَكِنْ إِذَا كَانَ قَلِيلًا وَوَقَعَتْ فِيهِ نَجَاسَةٌ تُخَالِطُهُ النَّجَاسَةُ وَتِلْكَ الَّتِي تُنَجِّسُ النَّاسَ، قُلْتُ: أَفَلَا يُطَهِّرُهَا إِذَا تَقَعُ فِيهِ؟ قَالَ: إِنَّمَا يُطَهِّرُهَا إِذَا يَمُرُّ عَلَيْهَا، قُلْتُ: وَمَا الْكَثِيرُ مِنَ الْمَاءِ؟ قَالَ: مَا لَا تُخَالِطُهُ النَّجَاسَةُ إِذَا تَقَعُ فِيهِ، قُلْتُ: وَمَا هُوَ؟ قَالَ: لَا عَلَيْكَ أَنْ تَتَحَرَّاهُ، قُلْتُ: أَرْشِدْنِي إِلَيْهِ فَإِنَّ النَّاسَ قَدِ اخْتَلَفُوا فِيهِ، قَالَ: مَا إِذَا تَحَرَّكَ جُزْئُهُ لَمْ يَتَحَرَّكْ كُلُّهُ، قُلْتُ: وَمَا مِقْدَارُهُ؟ قَالَ: قُلَّتَانِ وَهُمَا بِرْمِيلَانِ وَهُمَا كُرٌّ، قُلْتُ: وَمَا سَعَتُهُ بِالْأَشْبَارِ؟ قَالَ: سِتَّةٌ وَثَلَاثُونَ شِبْرًا، ثُمَّ قَالَ: اعْلَمْ أَنَّ اللَّهَ مَا فَرَضَ كُرًّا وَلَا أَشْبَارًا وَلَكِنَّ النَّاسَ لَمَّا جَاءُونَا حَيَارَى وَسَأَلُونَا نَظَرْنَا إِلَى مَا هُمْ عَلَيْهِ فَقَدَّرْنَا لَهُمْ»; “I heard Mansoor say: ‘Water does not become impure, and if it did, nothing would ever be purified.’ I said: ‘Does water in a small quantity not become impure when it comes into contact with an impurity?!’ He said: ‘Water does not become impure, but when the amount is small and an impurity falls into it, the impurity mixes with it, and it is the impurity that makes people impure.’ I said: ‘Does water not purify impurity when it falls into it?” He said: ‘It purifies it when it passes over it.’ I said: ‘What is kathir water?’ He said: “It is something that impurity does not mix with whenever it falls into it.’ I said: “What is that?’ He said: ‘You are not to (be blamed if you) determine it (yourself).’ I said: ‘Guide me to it; because people have disagreed about it.’ He said: ‘It is something that, when one part of it moves, the whole of it does not move.’ I said: ‘What is its amount?’ He said: ‘Two qullahs, and that is two barrels, and that is kurr.’ I said: ‘What is its volume in handspans?’ He said: ‘Thirty-six handspans (measured cubically—equivalent to 288 liters if each handspan is about 20 cm, 318 liters if each handspan is about 21 cm, and 384 liters if each handspan is about 22 cm).’ Then he said: ‘Know that Allah did not prescribe a kurr or handspans, but when people came to us in confusion and asked us, we looked at what they were upon, then we measured for them.’”

From here, it is understood that the specified amount for “kathir water” is only an approximate estimate based on common cases, and thus it should not be regarded as a fixed, devotional ruling. This is because the duty of the religiously accountable person is to avoid impurity; as Allah has said: ﴿وَالرُّجْزَ فَاهْجُرْ﴾[6]; “And avoid filth.” Therefore, whenever he knows that an impurity has spread throughout the water, he is obligated to avoid it. This occurs when a spreading impurity falls into a small amount of water, given that—even if it does not noticeably change the water’s color, smell, or taste—it naturally reaches all of it, and therefore, using it for drinking or wudu is contrary to hygiene and to the purity required for prayer. Nevertheless, if the religiously accountable person knows that the impurity that has fallen into the water has not reached all of it—due to the impurity being insignificant or dry, the wide surface area of the water, or some other reason—he can use it after removing the impurity itself and the surrounding water, even if the initial amount is less than the specified amount; as one of our companions informed us, saying:

«سَأَلْتُ الْمَنْصُورَ عَنْ سَطْلٍ مِنَ الْمَاءِ يَقَعُ فِيهِ قَطْرَةٌ مِنَ الدَّمِ، فَقَالَ: إِذَا عَلِمْتَ مَوْقِعَهَا فَخُذْ مِنْهُ كَفًّا قَبْلَ أَنْ تَنْتَشِرَ فِيهِ فَإِنِ انْتَشَرَتْ فِيهِ فَلَا تَشْرَبْ مِنْهُ وَلَا تَتَوَضَّأْ، قُلْتُ: فَإِنْ وَقَعَ فِيهِ نَجَاسَةٌ يَابِسَةٌ مِثْلُ شَيْءٍ مِنَ الْمَيْتَةِ وَلَمْ تَنْتَشِرْ فِيهِ فَتَرَى الشُّرْبَ وَالتَّوَضُّأَ مِنْهُ جَائِزًا؟ قَالَ: نَعَمْ»; “I asked Mansoor about a bucket of water that a drop of blood falls into. He said: ‘Whenever you know where it fell, before it spreads, take a handful from there. But if it spread throughout it, do not drink from it or use it for wudu.’ I said: ‘So if a dry impurity—like something from carrion—fell into it and did not spread throughout it, you consider it permissible to drink from it and use it for wudu?” He said: ‘Yes.’”

This view of His Eminence Mansoor—although contrary to that of other scholars—is the true view of the Ahl al-Bayt, reflected in numerous narrations from them. For example, it has been narrated from Abdullah ibn Yahya al-Kahili, who said: «سَمِعْتُ أَبَا عَبْدِ اللَّه عَلَیْهِ السَّلامُ يَقُولُ: إِذَا أَتَيْتَ مَاءً وَ فِيه قِلَّةٌ فَانْضِحْ عَنْ يَمِينِكَ وَ عَنْ يَسَارِكَ وَ بَيْنَ يَدَيْكَ وَ تَوَضَّأْ»[7]; “I heard Abu Abdullah (Ja‘far ibn Muhammad al-Sadiq) say: ‘Whenever you come to water and it is little, pour out (some) from your right, left, and in front of you, and (then) perform wudu,’” and from Abu Basir, who said: «قُلْتُ لِأَبِي عَبْدِ اللّهِ عَلَیْهِ السَّلامُ: إِنّا نُسافِرُ فَرُبَّما بُلِينا بِالْغَدِيرِ مِنَ الْمَطَرِ يَكُونُ إِلَى جانِبِ الْقَرْيَةِ فَتَكُونُ فِيهِ الْعَذِرَةُ وَ يَبُولُ فِيهِ الصَّبِيُّ وَ تَبُولُ فِيهِ الدّابَّةُ وَ تَرُوثُ فَقالَ: إِنْ عَرَضَ فِي قَلْبِكَ مِنْهُ شَيءٌ فَافْعَلْ هَكَذَا يَعْنِي افْرَجِ الْماءَ بِيَدِكَ ثُمَّ تَوَضَّأْ فَإنَّ الدِّينَ لَيْسَ بِمُضَيَّقٍ فَإنَّ اللّهَ عَزَّ وَجَلَّ يَقُولُ: ﴿مَا جَعَلَ عَلَيْكُمْ فِي الدِّينِ مِنْ حَرَجٍ﴾[8]»[9]; “I said to Abu Abdullah : ‘We travel, and sometimes we come across a rainwater pool near a village. So there is feces in it, children urinate in it, and livestock urinate and drop dung in it.’ He said: ‘If something of that is found in your heart, do this’—meaning, move the water away with your hand—‘because religion is not restrictive; as Allah, Exalted and Majestic, has said: And He has not placed hardship upon you in religion,’” and from Bakkar ibn Abi Bakr, who said: «قُلْتُ لِأَبِي عَبْدِ اللَّه عَلَیْهِ السَّلامُ: الرَّجُلُ يَضَعُ الْكُوزَ الَّذِي يَغْرِفُ بِه مِنَ الْحُبِّ فِي مَكَانٍ قَذِرٍ ثُمَّ يُدْخِلُه الْحُبَّ قَالَ: يَصُبُّ مِنَ الْمَاءِ ثَلَاثَةَ أَكُفٍّ ثُمَّ يَدْلُكُ الْكُوزَ»[10]; “I said to Abu Abdullah : ‘A man places the jug he uses to draw water from a vat in an unclean spot, then puts it back into the vat.’ He said: ‘He should pour out three handfuls of water (from the vat) and then wipe the jug,’” and from Abu Maryam al-Ansari, who said: «كُنْتُ مَعَ أَبِي عَبْدِ اللّهِ عَلَیْهِ السَّلامُ فِي حائِطٍ لَهُ فَحَضِرَتِ الصَّلاةُ فَنَزَحَ دَلْواً لِلْوُضُوءِ مِنْ رَكِيٍّ لَهُ فَخَرَجَ عَلَيْهِ قَطْعَةٌ مِنْ عَذِرَةٍ يابِسَةٍ فَأَكْفَأَ رَأْسَهُ وَ تَوَضَّأَ بِالْباقِي»[11]; “I was with Abu Abdullah in his garden. When it was time for prayer, he drew a bucket of water from the well for wudu. Then he saw a piece of dried feces on the surface of the water, so he tipped the mouth of the bucket (and poured out some of the water along with the impurity) and performed wudu with the rest,” and from Sama‘ah, who said: «سَأَلْتُهُ عَنِ الرَّجُلِ يَمُرُّ بِالْمَيْتَةِ فِي الْماءِ فَقالَ: يَتَوَضَّأُ مِنَ النّاحِيَةِ الَّتِي لَيْسَ فِيهَا الْمَيْتَةُ»[12]; “I asked him about a man who passes by carrion in water. He said: ‘He may perform wudu from the side where there is no carrion,’” and from Zurarah, who said: «قُلْتُ لَهُ [یَعْنِي لِأَبي جَعْفَرٍ عَلَیْهِ السَّلامُ] راوِيَةٌ مِنْ ماءٍ سَقَطَتْ فِيها فَأرَةٌ أَوْ جُرَذٌ أَوْ صَعْوَةٌ مَيْتَةٌ، قالَ: إِذا تَفَسَّخَ فِيها فَلا تَشْرَبْ مِنْ مائِها وَ لا تَتَوَضَّأْ مِنْها وَ إِنْ كانَ غَيْرَ مُتَفَسِّخٍ فَاشْرَبْ مِنْهُ وَ تَوَضَّأْ وَ اطْرَحِ الْمَيْتَةَ إِذا أَخْرَجْتَها طَرِيَّةً وَ كَذَلِكَ الْجَرَّةُ وَ حُبُّ الْماءِ وَ الْقِرْبَةُ وَ أَشْباهُ ذَلِكَ مِنْ أَوْعِيَةِ الْماءِ، قالَ: وَ قالَ أَبُو جَعْفَرٍ: إِذا كانَ الْماءُ أَكْثَرَ مِنْ راوِيَةٍ لَمْ يُنَجِّسْهُ شَيْءٌ تَفَسَّخَ فِيهِ أَوْ لَمْ يَتَفَسَّخْ إِلّا أَنْ يَجِيءَ لَهُ رِيحٌ يَغْلِبَ عَلَى رِيحِ الْماءِ»[13]; “I said to him [i.e., Abu Ja‘far al-Baqir ]: ‘In a rawiyah of water (a large container made from three hides), the carrion of a house mouse, a field mouse, or a sparrow has fallen.’ He said: ‘If it has disintegrated in it, do not drink from it or perform wudu with it. But if it has not disintegrated, then drink from it and perform wudu with it, and dispose of the carrion whenever you remove it fresh. It is also the same with water vessels such as earthen jugs, water vats, waterskins, and similar containers.’ Abu Ja‘far also said: ‘Whenever the water exceeds the amount of one rawiyah, nothing—whether disintegrated in it or not—makes it impure, except if a smell develops for it that overpowers the smell of the water.’”

From here, it is understood that the reason for the obligation to avoid “qalil water” (i.e., water in a small quantity) after impurity falls into it is solely because the impurity spreads throughout it. Therefore, whenever the impurity has not spread throughout it, avoiding it is not obligatory; rather, one can remove the impurity and the water around it, and use the rest. In other words, “qalil water” does not become impure the moment it comes into contact with impurity; rather, only the part of it that the impurity reaches becomes impure. Accordingly, an impurity that dissolves in water makes all of it impure; because it naturally reaches all its parts. However, an impurity that does not dissolve in water but remains distinct from it only makes the water directly around it impure. Rather, it does not even make the water directly around it impure; because, according to the principle «الْمَاءُ لَا يَنْجُسُ», water does not become impure but carries impurity (يَحْمِلُ الْخَبَثَ). Therefore, if the impurity is a solid object—such as fresh carrion from which no particles have detached—it is sufficient to remove it from “qalil water” without any need to reduce the amount of water. From here, it is understood that the doubt expressed by scholars regarding the irrationality of purifying impurity with “qalil water”—based on the assumption that it becomes impure upon contact with impurity—has no basis. This is because “qalil water” does not become impure upon contact with impurity, whether the impurity enters the water or the water flows over the impurity. Rather, when the impurity enters the water, it remains in it and may even spread, in which case using the water is not permissible; and when the water flows over the impurity, it removes the impurity and accordingly purifies it, in which case using the water is permissible.

3. Kathir water that has been changed by impurity becomes usable once the change is gone due to mixing with kathir water that has not been changed. Likewise, qalil water that has been mixed with impurity becomes usable after mixing with kathir water that is not mixed with impurity. Similarly, flowing water that has been changed by impurity becomes usable once the change is gone due to its natural gushing or flow. Of course, gushing waters without flow—such as well water or spring water that does not flow—are, due to their gushing nature, like running water; however, because of their lack of flow, they are like stagnant water and retain any impurity that falls into them. Therefore, if they are small in quantity, an amount proportional to the impurity that has fallen into them should be removed; however, if they are large in quantity and have not taken on the color, smell, or taste of the impurity, such removal is not obligatory.

4. Purifying impure things means removing impurity from them, which is naturally done with water; as Allah has said: ﴿وَيُنَزِّلُ عَلَيْكُمْ مِنَ السَّمَاءِ مَاءً لِيُطَهِّرَكُمْ بِهِ وَيُذْهِبَ عَنْكُمْ رِجْزَ الشَّيْطَانِ﴾[14]; “And He sends down upon you water from the sky to purify you with it and to remove from you the defilement of Satan,” and: ﴿إِنَّمَا يُرِيدُ اللَّهُ لِيُذْهِبَ عَنْكُمُ الرِّجْسَ أَهْلَ الْبَيْتِ وَيُطَهِّرَكُمْ تَطْهِيرًا﴾[15]; “Indeed, Allah wants to remove any impurity from you, O Ahl al-Bayt, and make you completely pure.” Therefore, whenever the impurity itself and the moisture resulting from it are removed by water passing over them, purity is achieved—as previously mentioned in the statement of Mansoor Hashemi Khorasani : «إِنَّمَا يُطَهِّرُهَا إِذَا يَمُرُّ عَلَيْهَا»; “It purifies it when it passes over it,” meaning that by passing over the place of impurity, it carries away both the impurity itself and the moisture resulting from it. Therefore, water must pass over the place of impurity without remaining there—whether by natural flow or by pressure—because if it remains in the place of impurity, it keeps the impurity there. Additionally, a single passing of water is sufficient as long as it removes the impurity itself and the moisture resulting from it, and there is no need for repetition.