Day Zero. It sounds like the name for an apocalyptic movie. Instead, the term has come to describe a similarly dire situation in the water sector: the day when the tap runs dry. In recent decades, several urban capitals, from Cape Town to Mexico City, have faced the threat of this label, emblematic of impending water crises around the world.
This year, I have been traveling the globe through Vanderbilt University’s Michael B. Keegan Traveling Fellowship. My project, influenced heavily by my years working within Vanderbilt’s Drinking Water Justice Lab, focuses on the disparities in how people experience drinking water in different communities. By Summer 2025, I will have met with legislators, innovators, philanthropists and researchers on this topic within Latin America, Europe, Asia, and Africa.
Starting in Mexico City this past August, I traversed Latin America, visiting communities in Colombia, Chile, Rapa Nui/Easter Island, Perú, Argentina, and Uruguay. I spent anywhere from a few days to a few weeks in each location, conversing with knowledgeable individuals to better understand the role of drinking water in different environmental systems. While it would be impossible to generalize the realities in each community to a city, region, or country, three main disparities persist: scarcity versus abundance, industrial versus human uses, and urban versus rural settings.
Disparity one: Scarcity vs. abundance
In Mexico City, I slept on the couch of a generous family in Iztapalapa, a colonia in which 43% of the population lives below the poverty line. Most locals do not drink the water from the tap, as they do not trust the safety of source waters, treatment, and infrastructure. Instead, they buy their drinking water in large jugs at their own expense, shipping them in on delivery trucks, called pipas. For cooking, cleaning, and bathing, many use water from unclean rooftop tanks and underground cisterns, when it is available. While there, I read a line in NPR that unfortunately resonated: “It’s rainy season in Mexico City, some streets are flooded and yet for many the taps are still dry.” In the short time I was there, both occurred.
Isla Urbana, a rainwater harvesting organization operating as both a nonprofit and a social enterprise, captures rainwater from rooftops before it floods the streets, transforming it into a sustainable source of clean water. While rainwater harvesting has existed for thousands of years, Isla Urbana has adapted the practice for the Mexican context. Co-founder Renata Fenton explained the influence of local culture in their project, as the Aztec revered Tlaloc, the rain god responsible for distributing the water held in the mountains, aided by his helpers, the tlaloques. In tribute, Isla Urbana’s main product is called Tlaloque, a square container with a signature blue color.
Increasingly, these blue tanks can be seen scattered among Mexican households, with expansion plans in Latin America. Their first-flush technology diverts the first few minutes of each rain from the water collection tank, taking air-borne debris and pollutants with it. When connected to an average roof, the Isla Urbana system can capture, treat, store, and supply all household water needs for 5–8 months in urban Mexico City or for up to 12 months in rural communities. With an added purification filter, the system can provide safe water for drinking.
Since 2009, Isla Urbana has installed 43,100 rainwater capture systems, harvesting 6.6 billion gallons annually. Their philanthropic program, Escuelas de Lluvia, or Rain Schools, provides their technology, along with an educational program, to 877 schools in Mexico that lack safe water infrastructure. With the politicization and hopelessness that the phrase Day Zero can generate, Isla Urbana aims to stimulate our collective consciousness and change our relationship with water with their most recent campaign: Día Uno, or Day One.
In the north of Argentina, near the provinces of Salta and Chaco, extreme drought poses similarly dry conditions as Mexico City. However, as one travels South, there is an abundance of water resources in the La Plata River Basin and the Guaraní aquifer. This abundance means there are less incentives for efficient water management. Water service providers in Argentina have leakage rates on average of 40-45%.
Turning abundance and improved efficiency into a national economic opportunity, Cámara Argentina del Agua, or the Argentine Water Chamber, has the slogan “Bringing Argentine water to the world.” CEO Gonzalo Meschengieser explained that Argentina’s water resources could be crucial in supporting development goals around Latin America and abroad.
Two key projects include the Argentina Water Exporting Group and their Water Responsible Companies Certification, a coalition of exporting companies and an eco-branding of water efficiency respectively. Because of Argentina’s isolated location geographically, the Argentina Water Exporting Group relies on the modality of virtual water. Virtual water is embedded or hidden in products, as it is a measure of water consumed throughout the value chain.
For instance, water-stressed Chile may import virtual water from Argentina through the purchase of resource-intensive products, like cereal crops or meat. The Water Responsible Companies certification adds assurances to consumers that Argentine companies are aware of methods to maximize the efficiency of their water use to ensure sustainability over the long term.
Disparity two: Industry vs. human uses
The disparity in water availability between north and south is perhaps more glaring in Chile, with Patagonian glaciers in the south and the Atacama Desert in the north. Currently, many Chilean municipalities rely on camiones aljibes, similar to the pipas of Mexico City, to deliver drinking water across this gradient. These tank trucks provide improved water access to northern areas, but also on a more local scale to those not connected to primary pipe networks.
However, this system creates a vulnerability for communities entirely reliant on delivery times and quantities for their livelihoods. Additionally, Chile’s length as a country, over 4,000 kilometers, makes vehicle delivery expensive and environmentally-taxing.
On the other hand, Chile’s coastline has created ample opportunity for desalination plants, or the process of removing salt from saltwater to add to its freshwater resources. Beyond drinking water, desalination also supports the water needs of Chile’s mining industry, with its immense deposits of copper, lithium, and other metals concentrated in the arid Atacama. Mining companies have invested heavily in desalination technology, needing the water to separate minerals, cool machinery and control dust (Source).
What happens with industrial water once it is used in a mine, a factory or a farm? With treatment of wastewater, it can be reused or safely deposited into waterways. Dr. Rodrigo Labatut at Pontificia Universidad Católica de Chile is researching a process called hydrothermal liquefaction to utilize the byproduct of wastewater treatment: sludge.
Hydrothermal liquefaction utilizes high temperature and pressure to accelerate the natural decay process of organic matter in the sludge, producing biocrude that can be refined into biofuel. Labatut gets his raw materials from key agricultural partners who see future applications of his work in their own processes. Thus, development of new innovations to promote resource efficiency and profitability at the industry level can also produce positive externalities for a more sustainable society as a whole.
The promotion of holistic frameworks, particularly OneWater, is crucial for more effective resource management. This adjustment requires an increasingly integrated approach across stakeholders in how we use, and reuse, all forms of water.
Disparity three: Urban vs. rural
In addition to geographical differences in water availability, there are also vast differences in governance structures between urban and rural areas. In Perú, for instance, urban households mostly receive their tap water from pipes, provided by water utilities. Water being a natural monopoly means that one utility often provides for the needs of an area. In Cusco, tap water is provided by Sedacusco, a public utility owned and controlled by the Peruvian government. Unsurprisingly, the leadership, directives and special projects of the water utilities are dictated by who is in power.
As one travels outside cities, however, governance structures entirely shift. Perú’s rural communities rely on Juntas Administradora de Servicios de Saneamiento, or JASS, to run their water and sanitation infrastructure. The JASS are composed of citizens themselves, who accept the communal responsibility despite the additional burden on their time.
Understandably, many JASS operate with insufficient expertise, aging infrastructure, and minimal resources. I spent an afternoon with Constantino Aucca Chutas, president of Peruvian NGO Asociación Ecosistemas Andinos (ECOAN), and his technical team. ECOAN has reforested 4.5 million endemic plants in Peruvian highlands, including rural communities in the conservation process. The roots of the native plants, they explained, can capture the heavy minerals being deposited as glaciers recede, naturally filtering the water.
The rural communities with which ECOAN engages overwhelmingly ask for help to improve water quality and accessibility. The JASS need technical experts to extend piping, test chlorine levels, and construct green infrastructure, but are often forgotten by municipalities who focus resources on urban utilities. Notably, this disparity between urban and rural governance persists amongst other Latin American countries as well, particularly Chile and Argentina.
Chutas explained that this dynamic can lead experts to “not recognize the local and traditional knowledge for water harvesting as was implemented by Incas 1000 years ago and is still working in some valleys along the Andes. We can see that gray infrastructure is failing and water scarcity is tackling the cities and rivers along the South American continent.” Thus, ECOAN also advocates for the respect and preservation of traditional conservation practices and green infrastructure.
Ultimately, the challenge of this article is condensing two months of travel into a few pages, while doing justice to the vast array of topics covered. Further conversations are warranted on the gender burden, impact of contaminants in healthcare settings, and children’s health, among others. These subjects deserve a lifetime of study, and I look forward to comparing key themes and disparities across continents. Next stop: Europe!
