Drought has drained the three reservoirs that provide about 60% of the water for the [Monterrey, Mexico] region’s 5 million residents. Most homes now receive water for only a few hours each morning. And on the city’s periphery, many taps have run completely dry. … “It should be a wake-up call,” said Samuel Sandoval Solis, an expert in water management at UC Davis who described the situation in Monterrey as a “crystal ball” for Southern California. Both are densely packed metropolitan centers that rely heavily on faraway water sources. … Southern California cities, which import about 55% of their water from the Colorado River and Northern California, have already been forced to reduce water usage and face the prospect of further cuts as drought persists …