The American West is suffering from a record drought, with the Colorado River's water level falling to its lowest in decades. Competition among states to secure water from the river, on which about 40 million people rely, is growing increasingly fierce. In the midst of this, San Diego, California, is trying to transform into a "water export city." Once a symbol of water scarcity, San Diego is now supplying surplus water to other states.
According to The Wall Street Journal (WSJ), Arizona and Nevada have recently been in talks with the San Diego County Water Authority to use desalinated seawater produced off the California coast. The move is seen as an effort to reduce dependence on the Colorado River using water from the Carlsbad desalination plant, the largest in North America.
This transaction does not physically move water. Instead, in exchange for covering the operating expenses of the desalination plant, the states would receive San Diego's allocated Colorado River water resources in a "rights exchange" structure. About 56,000 acre-feet per year is being discussed, enough to serve roughly 500,000 people.
San Diego's shift is no accident. The city endured a five-year megadrought in the early 1990s and faced a crisis in which it lost one-third of its water supply. To break away from a system that brought in most of its water from outside—and to ensure it would never face the same situation again—it began making massive investments. Over the next 30-plus years, San Diego poured huge expense into water resources self-sufficiency. It expanded dams to double storage capacity, built a seawater desalination plant, and proactively secured conserved water rights from agricultural areas in the Colorado River basin. As a result, outside dependence has fallen sharply from 95% in the past to about 10% today.
WSJ said a shift in public perception also played a role. San Diego's per capita water use has fallen by about half over the past 25 years. As supply rose and demand fell, the city ended up with unexpected surplus water resources. This structural change transformed San Diego from a "water import city" into a "supply city." A city that once bought water is now selling it.
San Diego now sees its surplus water as a new asset. In fact, local water resources authorities are actively considering supplying the surplus outside to reduce expense burdens. It is also a strategy to recoup the massive investment expense made for water self-reliance.
This trend is spreading across the American West. States facing shortages are securing new sources such as wastewater recycling and seawater desalination, while filling gaps through interstate water transactions. In the Los Angeles area, construction is also underway for a wastewater recycling facility large enough to serve up to 1.5 million people.
Technological change is supporting this. Recently, offshore desalination that removes salinity directly from deep seawater has been tested, part of efforts to reduce expense and environmental impact. In the long term, concepts are even being floated to build water resources production facilities at sea to produce and transact water.
San Diego is already ahead in wastewater recycling. Recycled water supplied under the name "Pure Water San Diego" has low mineral content and is used by local craft brewers. Experts say these changes are shifting how people view water. Analysis suggests that water, once a simple public good, is now becoming a resource for investment and transactions.