Source text
وَالْخَامِسُ: مَاءٌ مَشْكُوكٌ فِي طَهُورِيَّتِهِ وَهُوَ مَا شَرِبَ مِنْهُ حِمَارٌ أَوْ بَغْلٌ
• The fifth category is water whose purifying capacity is doubtful, not water known to be impure.
• The text identifies the leftover water of a donkey or mule for this category.
• The commentary also emphasizes a general principle: water is not declared impure merely because of suspicion; actual impurity must be known with certainty or strong probability.