Los Angeles imports a lot of water—fully 85 percent of the city’s water supply comes from outside sources, like the Sacramento-San Joaquin River Delta, the Colorado River, and the Sierra Nevada Mountains. That dependence on faraway resources makes L.A. extremely vulnerable.
For one thing, L.A. has no control over the political climate in those regions (and people don’t always love sharing their resources). Nor can we control the actual climate, and we’ve seen recently how a lack of snowfall in the mountains up north means dry fields and empty taps further south. Then there are natural disasters, like earthquakes, that could destroy the pipelines that bring outside water to the city. On top of all that, transporting water across long distances is wasteful and burns up energy, which worsens the global warming that led to California’s five-year drought.
To make L.A.’s water supply sustainable, Mayor Eric Garcetti created the Resilient Los Angeles Plan in March of 2018, which outlines a strategy for cutting our dependence on outside water in half by 2035.
According to the L.A. Times, capturing rainwater is essential to that goal, and could lead to full water independence by 2050:
The bigger question is could Los Angeles become entirely water self-sufficient by 2050? Even as we face climate change and population growth? The answer is yes, but it will require a modern, integrated approach to water management.
Stormwater is another local source we haven’t adequately tapped. Based on a DWP study, urban runoff can provide an additional 58,000 acre-feet of water, or about 11% of current annual use. But the potential is there for much more: In an average rainfall year, 270,000 acre-feet per year of stormwater ends up flowing down the L.A. River into the ocean. Funding for green stormwater infrastructure could come from the L.A. County Safe Clean Water Measure, which is expected to be on the ballot this November.