Luis Ramirez leapt onto the roof of his bright blue water truck to fill the plastic tank that by day’s end would empty into an assortment of buckets, barrels and cisterns in 100 homes.

It was barely 11 a.m. and Ramirez had many more stops to make on the hilly, grey fringes of Tijuana, a sprawling, industrial border city in northwestern Mexico where trucks or “pipas” like Ramirez’s provide the only drinking water for many people.

“Each time, it gets farther and farther where we have to go,” he said, blaming the city’s water problems on drought and population growth, before jumping into the driver’s seat next to 16-year-old assistant Daniel Alvarez.

Among the last cities downstream to receive water from the shrinking Colorado River, Tijuana is staring down a water crisis driven also by aging, inefficient infrastructure and successive governments that have done little to prepare the city for diminishing water in the region.