Musannaf Ibn Abi Shayba 1:1525

Abu Bakr narrated to us, he said: Abd al-Rahim and Abu Mu'awiyah narrated to us, from Muhammad ibn Ishaq, from Muhammad ibn Ja'far ibn al-Zubayr, from Abdullah ibn Umar, from Ibn Umar, who said: The Messenger of Allah, may Allah bless him and grant him peace, was asked about water that is in the wilderness and the beasts and animals that frequent it. He said: "When the water reaches two qullahs, it does not carry filth."