It is narrated from Sayyiduna Abu Sa'id al-Khudri (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) was asked about (the water of) the pools that were between Makkah and Madinah. They said: "Beasts of prey, dogs and donkeys come to drink from them?" The Messenger of Allah (peace and blessings be upon him) said: "What is in their bellies is theirs, and what remains is pure for us." (b) Abd al-Rahman bin Zayd is da'if (weak); his hadiths cannot be used as proof. (c) It has been narrated through another chain from Ibn Umar (may Allah be pleased with him) as marfu', and it is not well known.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 1220