Ground-Water Sources
A large ground-water basin exists under a portion of Orange County (roughly all of the area north of the Santa Ana and San Diego freeways interchange), giving officials a large receptacle to store and draw water from during a drought. Ground water accounts for 70% of all water used annually in the region overlying that basin, according to the Orange County Water District.
At right is the breakdown of the sources for the current ground-water supply. Applied water is water that percolates into the ground-water basin from people watering their lawns and such.
Orange County Water District Basin Cross Section
The underground basin has several layers of water, called aquifers, separated by clay barriers. Most of Orange County’s water is pumped from the upper and middle layers, about 1,000 feet deep. The deeper water is costly to reach, and often is poor quality.
Over 300 municipal wells serve the Orange County Water District.
Note: Drawings not to scale
Source: Orange County Water District
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