Abu Huraira reported God’s messenger as saying, “When a dog drinks out of a vessel belonging to any of you, he must wash it seven times,” (Bukhari and Muslim) In a version by Muslim he said, “When a dog laps the water in a vessel belonging to any of you, he must wash it seven times, using earth the first time.”

عَنْ أَبِي هُرَيْرَةَ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «إِذَا شَرِبَ الْكَلْبُ فِي إِنَاء أحدكُم فليغسله سبع مَرَّات» وَفِى رِوَايَةٍ لِمُسْلِمٍ: «طَهُورُ إِنَاءِ أَحَدِكُمْ إِذَا وَلَغَ فِيهِ الْكَلْبُ أَنْ يَغْسِلَهُ سَبْعَ مَرَّاتٍ أولَاهُنَّ بِالتُّرَابِ»