Is performing *Tahammum* (dry ablution) permissible when two water containers are present, one certainly pure and the other certainly impure?
Chapter on what purification is achieved with regarding water
Al-Mughni
Book of Purification
Primary text
If a traveler possesses two water containers, one certainly pure and the other certainly impure, and he has no other pure water, it is impermissible to arbitrarily select one (*taharri*) in either case (whether the pure water is equal in number to the impure or fewer). This ruling applies specifically to the travel state where *Tahammum* is permissible and water is often scarce. If pure water other than the two suspicious containers is found, purification (*Wudu*) must be performed with it, and neither arbitrary selection nor *Tahammum* is allowed, without dispute.
Supporting text
When the number of pure containers exceeds the impure ones, some scholars, like Abu Ali al-Najjad (among the Hanbali school) and Abu Hanifa, permit arbitrary selection (*taharri*) because the likelihood favors finding the pure water, and the side of permissibility is strengthened. Al-Shafi' permits selection in both cases, purifying with the majority by conjecture, analogizing it to the necessity of determining the Qibla for prayer. Ibn al-Majishun and Muhammad bin Muslima mandate performing *Wudu* from each container and praying with the first, with the latter adding that the effect of the first *Wudu* must be washed off.