This is [*Sleep Dealer*][1] (2008).

> The near future. Like tomorrow. In a world marked by closed borders, corporate warriors, and a global computer network, three strangers risk their lives to connect, break through the barriers of technology, and unseal their fates.
> 
> https://www.youtube.com/watch?v=nbJGQl-dJ6c&themeRefresh=1

This synopsis mentions the water and the drones.

> Memo (Luis Fernando Peña), a young Mexican, lives on a milpa in Santa
> Ana, Oaxaca with his family. Once, a river flowed through the milpa,
> which his father owns. But a few years ago, the Del Rio Water Company
> built a dam upstream. Now, residents of Santa Ana must pay $1/gallon
> to enter the facility and collect water.
> 
> In his spare time, Memo tinkers with discarded radio parts and builds
> an antenna to pick up voices from far away. One night, he overhears a
> transmission between Rudy (Jacob Vargas), a drone gunship operator,
> and his compatriots. His signal is detected, and tracked down to his
> family's shack in Santa Ana. Live on TV the next day, Rudy carries out
> a mission to neutralize an "aqua-terrorist intercept". As Memo and
> family watch on their TV, they soon realize that the target is the
> antenna on top of their shack. They run back to the shack, only to see
> it obliterated by a hovering drone gunship. As Memo's father crawls
> out of the building, Rudy gets confirmation that he is a known
> "aqua-terrorist", and Rudy fires a rocket at him, blowing him to bits.

  [1]: https://www.imdb.com/title/tt0804529/?ref_=ttpl_ov