Question
If someone has adjacent vessels of water that are equal in purity and impurity, and he does not possess anything else, how should he proceed to perform ablution?
Answer
I say, and with God's help: If they are equal in purity and impurity, then one should be cautious when drinking, and perform tayammum. It is preferable to mix them or pour them out and then perform tayammum; as the purifying agent is certainly absent. See: Al-Maraqi, p. 34, and God knows best.