Is the water supplied by the state to mosques, which is highly sought after in summer, considered an endowment for Allah Almighty upon entering the mosque, and what is the ruling on taking it from mosques?

The statement that water, if it enters a mosque, automatically becomes a وقف (waqf, endowment) for Allah Almighty is not absolutely correct. Rather, it requires elaboration, which can be understood from Fatwa No. 49798 and Fatwa No. 49988.