Yahya related to me from Malik from Abu'z-Zinad from al-Araj fromAbu Hurayra that the Messenger of Allah, may Allah bless him and granthim peace, said, "If a dog drinks from your vessel, wash it seventimes." (ES)
USC-MSA web (English) reference: Book 2, Hadith 36 (ES)
Arabic reference (ES): Book 2, Hadith 66 (ES)