Abu Sa'id al-Khudri (may Allah be pleased with him) narrates that a man asked the Messenger of Allah (ﷺ) and said: "Indeed, pieces of meat from dogs and cloths stained with menstrual blood are thrown into the well of Budā‘ah (the name of a well). (Can we attain purification with its water?)" So the Prophet (ﷺ) said: "Nothing makes water impure."
Hadith Referenceمسند الإمام الشافعي / كتاب الطهارة / 2
Hadith Takhrijأخرجه الترمذي: الطهارة، باب ماجاء أن الماء لا ينجسه شيء: (66) - وقال حديث حسن والنسائي، المياه، باب ذكر بئر بضاعة: (327) - وصححه ابن الجارود: (47).