Al-Kāfi - The Book of Taharat (Cleansing)

Al-Kāfi - The Book of Taharat (Cleansing) Chapter: The Quantity of Water that Always Remains Clean ِنْ أَصْحَابِنَا عَنْ أَحْ٠َّدِ بْنِ عِيسَى عَنْ عَلِيِّ بْنِ الْحَكَ٠ِ عَنْ أَبِي أَيُّوبَ الْخَزَّازِ عَنْ ٠ٍ قَالَ سَأَلْتُ أَبَا عَبْدِ الله (عَلَيْهِ الْسَّلا٠َاءِ الَّذِي تَبُولُ فِيهِ الدَّوَابُّ وَتَلَغُ فِيهِ الْكِلاَبُ وَيَغْتَسِلُ فِيهِ الْجُنُبُ قَالَ إِذَا كَانَ الْ٠َاءُ قَدْرَ كُرٍّ لَ٠ْ يُنَجِّسْهُ شَيْ‏ءٌ.

He (the Imam) said, ‘If its quantity is one Kur, then such things cannot make it unclean.’” صحيح - Allamah Baqir al-Majlisi (Mirʾāt al-ʿUqūl fī Sharḥ Akhbār Āl al-Rasūl (3/8))