Fresno is running out of phone numbers. In response, the California Public Utilities Commission will add a new area code within two years: 357.

The 559 area is expected to run out of numbers by September 2025, the commission said in a news release. No phone numbers will change, but once the 559 area code is exhausted, the 357 prefix will become available.

Dialing the new 357 area code will not incur long-distance charges, according to the CPUC. But for Central Valley users, it will mean remembering to dial 1 and the area code, even for local calls.

“The overlay alternative requires customers to dial 1 + area code + seven-digit telephone number for all calls, including local calls,” CPUC officials said.

Adding the Overlay ‘Most Equitable’ Alternative

The 559 area code includes all or portions of Fresno, Madera, Mariposa, Merced, Tulare, and Kings counties.

The North American Numbering Plan Administrator monitors the telephone numbering system for the U.S., Canada, and some Caribbean countries. It was NANPA who first forecasted the Central Valley’s need for an additional area code.

On Dec. 14, the CPUC approved the plan to add the 357 code.

In 1998, the CPUC split the 209 area code to form 559. That time, the commission split the numbers geographically. Telephone users’ numbers south of the 209 border had to change.

In 2022, the CPUC added a 350 overlay to the 209 area code region anchored by Stockton and Modesto.

The commission said that doing the overlay was the most “equitable and consumer-friendly alternative.”

US Phone Numbering System Finite

While the amount of phone numbers may seem vast, it is not infinite. The United States only has 800 area codes available to it — numbers beginning with 1 or 0 cannot be used.

Other prefixes, such as 9-1-1, 8-1-1, and more are equally invalid.

Electronics website How Stuff Works estimates 5 billion available phone numbers. In North America, more than half have been assigned.

The website reported in February that the number of area codes has grown from 86 when it first began in 1951 to 335 countrywide.