There’s no law in Chile that prevents producers from planting on hillsides, Professor Bauer explains, even though “it’s pretty obvious that it’s an unsustainable use of groundwater.” Chile’s semi-arid central valleys traditionally had vegetation only on the valley floor: The hillsides were barren.

There are currently no laws regulating water use in Chile. In 1981, under Augusto Pinochet’s dictatorship, water rights were privatized and then promptly over-allocated. In recent years, powerful landowners and politicians have been fined (link en Español) for stealing groundwater to which they don’t own the rights. As a result, a bill that would increase the fines for those who steal water has been slowly making its way (link en Español) through the Chilean Senate since January 2012 .

Climate change and drought have compounded Chile’s water problems in recent years. As the planet warms, more of Chile’s winter precipitation falls as rain and goes directly to the Pacific Ocean instead of getting stored in the country’s glaciers. As a result, glacial melt—which provides 20 to 25 percent of the summer flow in Chile’s rivers—has lessened. Several years of drought have added insult to injury.

Everyone proposes a different solution to this problem. Adolfo Ochagavía, a member of Palta Hass Chile—the largest avocado growers’ association in the country—argues the only problem is water capture and believes the solution lies in building more infrastructure, such as large reservoirs, for retaining water.

Felipe Martín, former president of the Chilean government’s National Irrigation Commission, says the solution lies in improving water users’ organizations in the Ligua Valley. These organizations, under Chilean law, should monitor water flow, determine how much water can and should be allocated, and ensure that no one takes more water than they are due. Carl Bauer, of the University of Arizona, says strengthening users’ organizations would be a good first step, but ultimately the government will need to institute some water regulation. And Rodrigo Mundaca, a water activist in the region, takes the most extreme stance: He calls for the nationalization of all of Chile’s water resources.

Ideally, both U.S. and Chilean consumers would also be able to help by trying to buy avocados grown by small farmers.

But that’s harder than it sounds. Juan Enrique Lazo, the president of Palta Hass Chile, estimates that 90 or 95 percent of the Chilean avocados sold in the U.S. come from large producers. Furthermore, most grocery stores won’t release information about the source of their avocados. That said, many of the avocados sold by U.S. supermarkets in the fall and winter come from Chile—and, of the many grocery stores we contacted for this report, only Trader Joe’s told us that they try to source avocados from smaller farms.

“When you eat an avocado that comes from [a large producer in] Chile, think about the fact that the water used to produce it is water that homes in the country’s most humble communities now lack,” says water activist Rodrigo Mundaca. “It’s water that the country’s men and women now don’t have for their basic needs.”