The 707 area code is expected to be depleted of available prefixes by December 2023. Pursuant to Federal Communications Commission (FCC) policy and CPUC rules, the CPUC must adopt an area code relief plan to provide additional numbering resources. A new area code will be introduced on top of the 707 area code using the overlay method, pending approval by the CPUC. The new area code will provide additional prefixes and new telephone numbers for customers requesting new telephone numbers.

For the 707 area code, an overlay is the only option to ensure the availability of telephone numbers in the geographic area. This is because the 707 area code, along with eight other California area codes, is in the process of transitioning to 1+10-digit dialing as ordered by the FCC due to the FCC’s designation of 988 as the 3-digit dialing code for the National Suicide Prevention Lifeline. 1+10-digit dialing will be fully in place in the 707 area code on October 24, 2021, and calls can no longer be made by dialing 7 digits. Thus, a split, which allows customers to retain 7-digit dialing, is not feasible for the 707 area code, and therefore, an overlay is the only option.

On April 16, 2021, the North American Numbering Plan Administrator (NANPA) filed Application A.21-04-009, requesting the Commission to adopt an overlay as the form of relief for the 707 area code.

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Background

The 707 area code was created in 1959 when it split off the 415 area code. The 707 area code serves portions of Del Norte, Glenn, Humboldt, Lake, Marin, Mendocino, Napa, Solano, Sonoma, Tehama and Trinity Counties. The 707 area code serves the cities of American Canyon, Arcata, Benicia, Calistoga, Clearlake, Cloverdale, Cotati, Crescent City, Dixon, Eureka, Fairfield, Ferndale, Fort Bragg, Healdsburg, Lakeport, Napa, Novato, Petaluma, Point Arena, Rio Dell, Rio Vista, Rohnert Park, Saint Helena, Santa Rosa, Sebastopol, Sonoma, Suisun City, Trinidad, Ukiah, Vacaville, Vallejo, Windsor, Willits, and Yountville, as well as unincorporated communities.