✅ Answer: Pay attention to the following narrations:

1⃣عن أَبِي عَبْداللَّه قال: إِذَا كَانَ الْمَاءُ قَدْرَ كُرٍّ لَمْ يُنَجِّسْهُ شَيْءٌ

📚 Istibsar, Vol. 1, p. 6

Imam Sadiq, peace be upon him, said: When water reaches the amount of kurr, nothing can make it impure!

2⃣ Shihab says: I went to Imam Sadiq, peace be upon him, to ask him a question. The Imam began speaking to me and said: If you wish to ask, do so, or if you wish, I will inform you!

I said: Inform me!

He said: You’ve come to ask about a pond next to which there is a carcass—whether you should perform wudu from it or not!

I said: Yes! He said: Perform wudu from the other side of the pond unless the smell of the carcass has overcome the water!

And you’ve come to ask about the stagnant water of a well! As long as there is no change or overpowering smell, there is no problem!

I said: What is a change? He said: Yellowness!

So, (if there is no change in color or smell), perform wudu from it, and whatever water is abundant enough to overcome is pure and clean!

📚 Basa’ir al-Darajat, Vol. 5, Chapter 10, p. 64

3⃣عن أَبِي بَصِير قال: سَأَلْتُ أَبَا عَبْداللَّه عَنِ الْكُرِّ مِنَ الْمَاءِ كَمْ يَكُونُ قَدْرُهُ قَالَ إِذَا كَانَ الْمَاءُ ثَلَاثَةَ أَشْبَارٍ وَ نِصْفٍ [نِصْفاً] فِي مِثْلِهِ ثَلَاثَةُ أَشْبَارٍ وَ نِصْفٌ فِي عُمْقِهِ فِي الْأَرْضِ فَذَلِكَ الْكُرُّ مِنَ الْمَاءِ

📚 Kafi, Vol. 3, p. 3

Abi Basir says: I asked Imam Sadiq, peace be upon him, about kurr water—how much is it? He said: When water is 3.5 spans by 3.5 spans by 3.5 spans deep in the ground, that amount is kurr!

3⃣إِسْمَاعِيل بْنِ جَابِر قال: سَأَلْتُ أَبَا عَبْداللَّه عَنِ الْمَاءِ الَّذِي لَا يُنَجِّسُهُ شَيْءٌ فَقَالَ كُرٌّ قُلْتُ وَ مَا الْكُرُّ قَالَ ثَلَاثَةُ أَشْبَارٍ فِي ثَلَاثَةِ أَشْبَار

📚 Kafi, Vol. 3, p. 3

Ismail ibn Jabir says: I asked Imam Sadiq, peace be upon him, about water that nothing can make impure; he said: One kurr. I said: What is a kurr? He said: Three spans by three spans!

4⃣عن الْحَسَن بْنِ صَالِح الثَّوْرِيِّ عَنْ أَبِي عَبْداللَّه فی حدیث قَالَ: قُلْتُ وَ كَمِ الْكُرُّ قَالَ ثَلَاثَةُ أَشْبَارٍ وَ نِصْفٌ عُمْقُهَا فِي ثَلَاثَةِ أَشْبَارٍ وَ نِصْفٍ عَرْضِهَا

📚 Kafi, Vol. 3, p. 2

Hasan ibn Salih says in a narration: I said to Imam Sadiq, peace be upon him: How much is a kurr? He said: 3.5 spans deep by 3.5 spans wide!

5⃣ عن أَبِي عَبْداللَّه قال: الْكُرُّ مِنَ الْمَاءِ الَّذِي لَا يُنَجِّسُهُ شَيْ ءٌ أَلْفٌ وَ مِائَتَا رِطْلٍ

📚 Kafi, Vol. 3, p. 3

Imam Sadiq, peace be upon him, said: A kurr of water, which nothing can make impure, is 1,200 ratls!

✅ According to Shia narrations, if water reaches the amount of kurr, it does not become impure upon contact with impurity unless a change in its color or smell occurs due to the impurity, as mentioned in narrations 1⃣ and 2⃣.

✅ Various criteria for determining the amount of kurr are found in narrations, some of which are vague, while others are rare and impractical.

However, the two well-known narrational criteria used are the volumetric criterion and the weight criterion.

The volumetric criterion itself has varying narrations, with one prominent version being a volume of 3.5 spans in length, width, and height.

Considering the average span (wajb) as approximately 22 centimeters, a kurr would be a container about 77 centimeters in length, width, and height, which amounts to approximately 457 liters and roughly the same in kilograms of water.

✅ Another criterion is calculation by ratl, as per narration 5⃣, where each kurr equals 1,200 (Iraqi) ratls. According to the analysis and calculation in Question 796, each Iraqi ratl is approximately 383.76 grams, resulting in a kurr of about 460.5 kilograms.

Thus, based on the criterion of 3.5 spans, a kurr is approximately 457 kilograms, and with the weight-based calculation of ratl using barley grains, it is about 460 kilograms. These two figures are very close and show little difference.

However, other calculation methods have arrived at different weights. As explained in Question 796, some calculate the sa’ as 2,831 grams based on the well-known weight of a legal mithqal and dinar. Since narrations establish that each sa’ equals 9 Iraqi ratls, each ratl would be about 314.555 grams. Thus, according to narration 5⃣, a kurr would be approximately 377 kilograms. This method relies less on narrations and shows a significant discrepancy with the span-based criterion, making the method we mentioned earlier more robust.

✅ To understand how the ratl is calculated using the two well-known methods, which also form the basis for the weight-based calculation of kurr, be sure to refer to Question 796 at the link below:

https://t.me/porseshvapasokhe/1300