Question:
If a small amount of used water/ma mustamal gets mixed with an amount of water/ma mutlaq that is less than qullatayn, does the water/ma mutlaq become used/mustamal. For example, if a person takes a bath/ghusl from a small bucket and drops of the water from his body fall back into the bucket?
Answer:
Drops of used water [ma mustamal] have fallen into another water. The ruling of the drops is that they are used; the ruling of the other water is that it is used if the drops are many. (Fath al-Aziz 1/397-98: Khabaya al-Zawaya 41-42)
And, Allah knows best.
Shafiifiqh.com Fatwa Dept.