I say, with Allah's guidance: Milk has two characteristics: color and taste, and it has no smell. If one of these characteristics appears in the water, it becomes pure but not purifying for ritual impurity. It is permissible to remove actual impurities with it, but it is not permissible to perform ablution or ritual bathing with it. See: Al-Lubab, 1/18-19, and Al-Hadiyah Al-Alaiyah, p. 39-40, and Allah knows best.