Does the foot of a person, wet from walking through puddles that have dried after dogs drank from them, become impure?

The general rule is that puddles in the streets are excused, even if some of them are ritually impure (najis), as long as the impurity itself is not directly touched. A wet foot does not become impure by stepping on dry puddles unless one is certain of stepping on the impurity itself. Similarly, dogs drinking from a pool of water does not render it impure if its volume reaches two qullahs (approximately 160.5 liters).