Messenger of Allah ﷺ said, "One should not prevent others from watering their animals with the surplus of his water in order to prevent them from benefiting by the surplus of grass."  

أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ لاَ يُمْنَعُ فَضْلُ الْمَاءِ لِيُمْنَعَ بِهِ فَضْلُ الْكَلإِ