RIO VERDE FOOTHILLS, Ariz. — More than 500 homes in this affluent desert community that boasts mountain views, ample trees and ranches hidden in the crooks of scrubby hills will run out of water by year's end as drought tightens its grip on the West.“Some of us will borrow water from a friend’s well, others will have to pay a water hauler from far away.”As climate change makes the western United States hotter and drier, the looming crisis in Rio Verde Foothills exemplifies how cities and states could be forced to vie for a diminishing amount of the natural resource.But a year ago, Scottsdale notified Rio Verde homeowners that its water supply would be limited to only city residents starting Jan. 1, 2023, barring trucking companies from purchasing and exporting its water.A Canada-based water company, Epcor Utilities, filed an application in October to supply Rio Verde Foothills with water, said Nick Debus, a spokesman for the Arizona Corporation Commission, a state agency that regulates private water.Thomas Loquvam, general counsel for Epcor, said the commission asked the utility to provide water for residents, who would foot the bill for the project, resulting in the higher rates."