Fog Nets — Drinking Water from Mist
On one of the driest coastlines on Earth, communities pull clean water out of the fog. The water was always there — what was missing was the net.
At a glance
Origin: The fog collector — the atrapanieblas — was invented in Chile in 1954 by physicist Carlos Espinosa Arancibia, in drought-stricken Antofagasta. He donated the patent to the Universidad Católica del Norte and, through it, to UNESCO, so any community that needed it could use it freely. Building on his freely-shared design, a Pontificia Universidad Católica de Chile team — Pilar Cereceda, Horacio Larraín and Nazareno Carvajal — began the El Tofo–Chungungo research in the Coquimbo Region from 1980; the large-scale system followed in 1987 with fog scientist Robert Schemenauer and Canadian support.
Maturity: Scaled — operational in 25+ countries, with continuous replication since 1992.
Cost: a small test collector runs US$75–200; a large 40 m² collector US$1 000–1 500; a village system ~US$15 000.
Energy: none. Entirely passive — wind carries the fog through the mesh, gravity carries the water to the tank.
Licence: Open. The design was published freely and taught openly — given away to the world from Espinosa onward.
The story
Chile’s northern coast runs along the edge of the Atacama, the driest non-polar desert on Earth, where some parts have never recorded a single drop of rain. El Tofo itself sits further south, in the semi-arid Coquimbo Region — dry, but not the desert’s hyper-arid core. But every winter, a thick Pacific fog called the Camanchaca rolls in from the ocean and blankets the coastal mountains. Local communities always knew the fog was there. What they couldn't do was drink it.
Catching this fog was not a new idea. In 1954, in drought-stricken Antofagasta further north, the Chilean physicist Carlos Espinosa Arancibia built the first fog collectors and then gave his invention away — he donated the patent to the Universidad Católica del Norte, which passed it to UNESCO so any community that needed it could use it freely. In 1980, a team of geographers from the Universidad Católica de Chile — Pilar Cereceda, Horacio Larraín and Nazareno Carvajal — began studying whether the Camanchaca could be harvested at El Tofo, above the fishing village of Chungungo. The first people they turned to were Espinosa and his collaborators, who shared their work generously. In 1987, with fog scientist Robert Schemenauer and support from Canada’s environment ministry, they built the first large-scale system on the mountain, above a village with no piped water, dependent on trucked deliveries that sometimes came days apart.
In May 1992, after a seven-kilometre pipeline carried the collected water down to the village, water flowed from taps in Chungungo for the first time in history. Residents called it a miracle. The system produced an average of 15 000 litres a day, and the knowledge was shared freely — fog collection projects now run in more than 25 countries.
How it maps to UnaMente: mist → net → water is minds → UnaMente → solutions. The fog net isn't just the logo — it's the whole idea.
The problem it solves
Communities in arid coastal and mountain areas with regular fog but little rainfall have no reliable clean water. Trucked water is expensive and unreliable; groundwater is often absent or contaminated.
Fog nets offer a passive, electricity-free, locally maintainable alternative — using the one weather resource these communities have in abundance.
How it works
A fine double-layer mesh is stretched between two poles, facing the fog-bearing wind. As fog passes through, tiny droplets cling to the threads, merge, and run down into a collection trough, then through a simple sand filter to a storage tank.
The single most important step is site selection — the right location matters more than the quality of construction. Always install a small 1m² test collector for a full fog season before building anything larger, to confirm how much water your site can actually produce.
What to expect — and what not to
In good conditions, a 40m² collector can produce 150–750 litres per day during fog season.
• Water quality typically meets WHO drinking water standards — but treat or boil if uncertain.
• Can last 10+ years with basic maintenance.
• Needs regular fog with wind behind it — visibility must drop below roughly 100 metres for effective collection (a useful rule of thumb rather than a hard threshold — measure the yield at your own site). Humidity or haze alone won't do.
• Does NOT work inland without coastal/mountain fog, on flat low-lying land, or for high-demand urban water needs. It cannot produce water on demand — yield depends entirely on the weather.
When it doesn't work — the honest part
The original Chungungo system fell into disrepair in the early 2000s — and the reason is the most valuable lesson in the whole story. It did NOT fail because the technology was bad. It worked, and the village grew from about 300 people to 600+ (some accounts say the town reached 900). That growth was a success — it reversed migration and brought gardens, fruit trees, and electricity.
It failed because of people, not physics. Around 2000, local officials chose to stop maintaining the fog system and lobbied instead for a conventional pipeline. Community ownership was weak and there was no funding model for upkeep. By 2002, only 9 of the original 94 collectors were still standing. A conventional pipeline was chosen over maintaining and extending the fog system, at far greater cost.
The lesson UnaMente draws from this: a technology can work exactly as designed and still be abandoned if no one commits to maintaining it. Any community deploying fog nets must plan for growth, for local ownership, and for long-term commitment from the very start.
Credit & licence
Fog collection in Chile was pioneered by physicist Carlos Espinosa Arancibia (1954, Antofagasta), who donated his patent to the Universidad Católica del Norte and, through it, to UNESCO for free worldwide use. The El Tofo–Chungungo work was carried out from 1980 by geographers Pilar Cereceda, Horacio Larraín and Nazareno Carvajal (Pontificia Universidad Católica de Chile), building on Espinosa’s freely-shared designs; the 1987 large-scale system was built with Robert Schemenauer (Environment Canada / FogQuest), CONAF and Canada’s IDRC. The core design remains free; the nonprofit FogQuest carries the work forward and publishes a free construction manual. Commercial engineered variants (such as the CloudFisher) carry separate licences.
For build guidance and support, FogQuest (fogquest.org) is the organisation to contact — their whole purpose is helping communities replicate fog collection.
