San Diego imports 80 percent of its water, with the Colorado River supplying about 63 percent, and 20 percent coming from Sierra Nevada runoff funneled from northern California via the State Water Project. The remaining 17 percent comes from local sources – a mix of rainwater, groundwater, desalination and recycled water.

While these numbers vary from year to year, what hasn’t changed is the fact that San Diego has relied heavily on imported water for many decades. With climate change heralding warmer weather and prolonged droughts, this impacts the level of snowpack and river flow, which in turn threatens the region’s water security.