The Messenger of Allah ﷺ was asked about water and the animals and predators that frequent it. He replied, "When the water reaches two qullahs, it does not carry impurity."
أخبرنا هناد بن السري والحسين بن حريث عن أبي أسامة عن الوليد بن كثير عن محمد بن جعفر
سئل رسول الله ﷺ عن الماء وما ينوبه من الدواب والسباع فقال إذا كان الماء قلتين لم يحمل الخبث
Its isnad is sahih. Abu Dawud narrated it in the Book of Purification, the chapter on what makes water impure, (63), from the hadith of Abu Usama, through him, and it is in Al-Kubra, hadith (50). Ibn Hibban graded it sahih (Mawarid) (118), as did Hakim, 1/132, 133, along with Shafii, Ahmad, Ibn Khuzayma, and others.