Used Water (Ma' Musta'mal)

Question

What do the scholars of the religion say about the following issue? Zayd says that if water has been put in a jug for wudu and a finger of the person making wudu, or the finger of some other person who is without wudu, falls into it, that water becomes used water (ma' musta'mal), and making wudu with it is then not permissible. When does water become used, and through the falling of how much of a limb into the water does it become used?

Answer

Wudu with used water is not permissible; but if used and unused water are mixed and the unused is more, wudu is permissible, because according to the position on which fatwa is given (mufta bihi) and the preferred position, used water is pure but not purifying (tahir ghayr mutahhir).

Source: Fatawa Mahmudiyya

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