The San Diego County Water Authority is developing a water shortage contingency plan, though not implementing it, despite dry conditions in places from which the region imports much of its water.

The region draws about 20% of its water from local sources, including groundwater, desalinated seawater and local reservoirs, according to the Authority’s website. Fully one-half of regional water is imported, by various means, from the Colorado River. A minority proportion comes from Northern California.