New rule: the data centers are allowed to use unprocessed water. Their output is now potable water that is tested by an independent source and certified to be of the required quality.

Optional: they can only use sea water and the output is the same: potable treated water. They can have all the water they want for free. Just desalinize it and give it to the people.

No you cannot just throw the resultant salt waste into the landfill. You gotta dispose of that shit on your dime, properly.