Could Fog Harvesting Solve California's Water Shortages?

California has long struggled with chronic drought and water scarcity—Newsweek spoke to two experts about whether capturing water from fog may be able to help.

They were both optimistic about using fog harvesting for California, which is being explored there with several research initiatives and pilot projects, but warned that it probably "can't produce water for all of the needs and demands of humans and society."

Water Shortages in California

The state has a dry Mediterranean climate with rainfall concentrated in the winter months—California gets half its yearly precipitation from December through February.

Its natural water resources rely on seasonal snowmelt and last month, California's Department of Water Resources warned of an especially dry forecast given the state's snowpack levels thanks, in part, to an abnormally dry January.

The state uses energy-intensive methods of desalination and water transportation, something that has been criticized by environmentalists, including the advocacy group Food and Water Watch, which has called for California to transition to renewable energy.

What Is Fog Harvesting?

Fog harvesting is the practice of capturing tiny water droplets from fog with specialized mesh nets. It was invented in the 1970s by the Chilean physicist Carlos Espinosa, who was trying to find solutions to a drought affecting Antofagasta the time.

It is low-cost and sustainable, as it requires no electricity, but it requires consistent fog and is heavily dependent on the weather.

Can Fog Harvesting Be Used in California?

Brook Kennedy, an associate professor in Industrial Design at Virginia Tech, told Newsweek: "Fog harvesting can absolutely be used in the United States, especially in coastal California that develops/ receives fog moving onto land from the Pacific."

He added that while the practice "does not provide enough water for all of the needs of industry and society...it can provide for decentralized water used for basic needs such as agriculture and some drinking."

Professor Daniel Fernandez, who carries out research at California State University, Monterey Bay's Fog Collection Project, told Newsweek that there are opportunities in coastal California for fog harvesting.

"Under some conditions, fog water harvesting is possible and I am doing it (or have done it) at a research-level scale at dozens of locations throughout California," he said.

One of these locations is near the California State University library, where Fernandez has deployed 10 fog collectors to support sapling oak trees.

He said fog collection could be used where it is "practical in locations without regular access to water for some applications"—for example, fire management, reforestation, small-scale farming or local flora and fauna.

But Fernandez warned: "Location needs to be one with the proper fog conditions, which puts a geographical limit on applicability. Additionally, the infrastructure would need to be maintained and the amounts collected will not practically scale to the amount of water used by large communities."

Where Is Fog Harvesting Happening in California?

Fernandez said several local authorities have "expressed interest" in fog collection, including the Daly City water treatment plant, which has deployed several fog collectors with him.

North Coast County Water District in Pacifica has collaborated with scientists to study how much water can be harvested from fog on water district lands on Milagra Ridge. It also runs a program where residents are offered fog collector garden beds.

Another major initiative is Fog Water Harvesting Solutions for Coastal California at the University of California, in Santa Cruz. In the summer of 2023, their fog collectors provided around 37 percent of the irrigation needs for a vegetable garden at the UCSC Farm.