Delta- 14% of the membership.

The Delta region serves Members in Alpine Amador, Butte, Calaveras, Colusa, El Dorado, Glenn, Inyo, Lake, Lassen, Mariposa, Merced, Modoc, Mono, Nevada, Placer, Plumas, Sacramento, San Joaquin, Shasta, Siskiyou, facilities to the east of Fairfield and south of Highway 12 in Solano County, Stanislaus, Sutter, Tehama, Trinity, Tuolumne, Yolo, and Yuba County.

Golden Gate 30% of the membership.

The Golden Gate region serves facilities in the City of San Francisco and south to San Mateo County to Highway 92, and all facilities located in Marin, Sonoma, Mendocino, Humboldt, Del Norte, Alameda, Contra Costa and Napa Counties, and Solano County west of Fairfield. 

Inland Empire 9% of the membership.

The Inland Empire region serves facilities east of Interstate 605 in Los Angeles County, in San Bernardino and Riverside Counties, and north of Highway 91 in Orange County. 

Los Angeles Valleys 25% of the membership.

The Los Angeles Valleys region serves facilities in Los Angeles County bounded by Ventura County on the west, the southern Kern County line on the north, from Route 395/Route 14 at Edwards Air Force Base south to the intersection of Interstate 605 and Interstate 10, and on the south by Interstate 10 to the ocean. 

Los Padres 2% of the membership.

The Los Padres region serves facilities in San Luis Obispo, Santa Barbara and Ventura Counties. 

San Diego 5% of the membership.

The San Diego region serves facilities in San Diego and Imperial Counties. 

Santa Rey 9% of the membership.

The Santa Rey region serves facilities south of Highway 92 in San Mateo County, and all facilities located in Santa Cruz, Monterey, San Benito and Santa Clara Counties. 

Sequoia 3% of the membership.

The Sequoia region serves facilities in Fresno, Inyo, Kern, Kings, Madera, Merced, and Tulare counties.