What should we do if a pig licks a vessel? What is the ruling on drinking from a well in which a dog or a pig has licked? Is it permissible to drink from a well or a flowing spring in an area where dogs are numerous?

The preponderant opinion regarding a vessel licked by a pig is that it should be washed once, unlike a dog. If a dog or a pig licks water that is more than two qullas (a large measure of water), it does not become impure unless its characteristics change. There is no harm in drinking from wells and flowing waters in areas where dogs are found, because their licking in them is not certain, and because such waters are usually abundant and not easily affected. Jurists have used the actions of the Companions and the fatwas of the Tābi‘īn (followers of the Companions) as evidence for the purity of such waters, even if wild animals and dogs frequent them.