"It was said: 'O Messenger of Allah, you perform Wudu' from the well into which the bodies of dogs, menstrual rags and garbage are thrown?' He said: 'Water is pure and it is not made impure by anything.'" (Using translation from Nasāʾī 326)
أَنَّهُ قِيلَ لِرَسُولِ اللهِ ﷺ يَا رَسُولَ اللهِ أَتَتَوَضَّأُ مِنْ بِئْرِ بُضَاعَةَ وَهِيَ بِئْرٌ يُطْرَحُ فِيهَا الْمَحِيضُ وَلُحُومُ الْكِلَابِ وَالنَّتْنُ؟ فَقَالَ رَسُولُ اللهِ ﷺ إِنَّ الْمَاءَ طَهُورٌ لَا يُنَجِّسُهُ شَيْءٌ