Star Wars-Style Fog Collectors Could Provide Water to the World’s Driest Cities

With less than 0.04 inches of rainfall each year, cities in Chile’s barren Atacama Desert—one of the driest places in the world—collect their water from ancient underground water sources. Now, researchers have identified another simple method that could help address water scarcity.

An international team of researchers in Chile has tested the viability of a water-collection method that could be straight out of Dune: fog harvesting. The technology also brings Star Wars to mind, namely the moisture farmers of Tatooine. The practice could bring significant relief to people living in poor, informal settings without access to a stable water source, according to the study, published today in the journal Frontiers in Environmental Science,

“The collection and use of water, especially from non-conventional sources such as fog water, represents a key opportunity to improve the quality of life of inhabitants,” Virginia Carter, an expert in sustainable development at the Universidad Mayor and first co-author of the study, said in a Frontiers statement. Carter and her colleagues conducted their study in the rapidly-growing municipality of Alto Hospicio, where around 10,000 people live in informal settlements—only 1.6 percent of which are connected to water distribution networks.

The team used simple fog collectors: very fine nets, or mesh, held aloft by two poles. Moisture in the air condenses into droplets on the material, which then flow into a gutter and into a water tank. Though their methods are not quite as innovative as sci-fi stillsuits that recycle urine into drinkable water (that currently seems reserved for space exploration), the fog collectors are passive systems that don’t require electricity or other energy to function.

“By showcasing its potential in Alto Hospicio, one of Chile’s most stigmatized yet rapidly urbanizing cities, this study lays the groundwork for broader adoption in other water-scarce urban areas,” said Nathalie Verbrugghe, an engineer at Université libre de Bruxelles and another first co-author of the study.

Carter, Verbrugghe, and their colleagues revealed that 38.61 square miles (100 square kilometers) could yield between 0.05 and 1.32 gallons (0.2 and five liters) of fog water per 10.76 square feet (one square meter) per day. August and September were the peak months for fog water collection, with researchers gathering up to 2.64 gallons (10 liters) per 10.76 square foot (one square meter) per day.

“This research represents a notable shift in the perception of fog water use—from a rural, rather small-scale solution to a practical water resource for cities,” Carter explained.

The researchers estimate that a relatively small area of mesh could collect enough water to irrigate Alto Hospicio’s green spaces. Scaling up the system with larger fog collectors could even provide enough water to meet the weekly needs of the city’s informal settlements. They also suggest that fog water could be used for soil-free farming, potentially producing up to 44 pounds (20 kilograms) of leafy greens each month.

The researchers do point out some shortcomings to their analysis. Their promising results came from fog collectors in higher altitudes outside of the city’s limits, so their regular use would require significant distribution infrastructure in addition to large storage systems. Other “key prerequisites include fog density, suitable wind patterns, and well-oriented elevated landforms. Additionally, since fog is seasonal in many regions, this variability should be considered,” said Verbrugghe. In fact, Carter emphasized that “fog can serve as a complementary urban water supply,” and not a comprehensive solution to water scarcity.

However, the team still hopes “to encourage policymakers to integrate this renewable source into national water strategies,” concluded Carter. “This could enhance urban resilience to climate change and rapid urbanization while improving access to clean water.”

While fog harvesting alone will not solve water scarcity, it ultimately represents an innovative and sustainable water collection method that could one day become an important tool in desert communities’ water management.