The 909 is running out of phone numbers.

The California Public Utilities Commission is aiming to introduce a new area code to the region served by the 909 — which includes cities from Walnut to Yucaipa along the 10 Freeway — because the number of available prefixes are expected to run dry in two years, CPUC spokeswoman Constance Gordon said in an emailed statement.

The new area code — whose three-digit number has not been announced yet — is expected to debut by September 2018 to avoid any service disruptions.

The new area code would be an “overlay,” which means existing 909 area code holders will be able to keep their numbers, said Joe Cocke, senior area code relief planner for the North American Numbering Plan Administration, the organization responsible for creating new area codes in the United States and Canada.

The overlay process differs from the geographic split method, which the CPUC chose when the 909 area code was carved out of the 714 area code’s region in 1992. In decades past, 714 was the area code for east and south of Los Angeles, including the Inland Empire, Orange and San Diego counties.

In a geographic split, which also occurred when Riverside County broke off from the 909 to become the 951 in 2004, Cocke said, existing phone numbers must be changed, which is difficult for residents and businesses.

Cocke said the overlay method, which places the new area code within an existing area code region, makes more economic sense.

“Having to change your area code has a negative impact to residential and business customers,” Cocke said in a phone interview. “It’s not an easy thing to have a geographic split. With overlays, you don’t end up having anybody negatively impacted.”

Judi Penman, president and CEO of the San Bernardino Area Chamber of Commerce, agreed.

“It’s much better this way,” Penman said in a phone interview. “It is definitely an inconvenience for businesses to change their phone numbers.”

Kathie Thurston, executive director of the Redlands Chamber of Commerce, remembers the difficulties businesses faced when the 909 was born.

“The hardship was having to change the numbers, ergo, change everything that occurs in business: your envelopes, your returns, invoicing and everything that goes along with it,” Thurston said in a phone interview. “So I think there’s been more thought put into it this time around and more consideration of what the impact is.”

Marcia Godwin remembers the hassle back in 2004, when the 951 area split from the 909. The associate professor of Public Administration at the University of La Verne was working for the city of Chino at the time, girding its emergency preparedness plans. She recalls the nuisance of having to verify employee contact numbers for those who had suddenly disappeared from the 909.

“Just about everybody had a cellphone, and it was difficult to keep that up to date,” said Godwin, who added she was happy to hear the CPUC plan is to use the overlay method for new numbers.

The CPUC plans to hold three local meetings to discuss the potential changes and to hear any concerns:

• The Pomona meeting will be 1 p.m. April 4 at City Council chambers, 505 S. Garey Ave.

• The San Bernardino meeting will be 6 p.m. April 4 at the Ruben Campos Community Center, 1717 W. Fifth St.

• The Redlands meeting will be 11 a.m. April 5 at the Redlands Community Center, 111 W. Lugonia Ave.

For those unable to attend, written comments may be mailed to the CPUC Public Advisor’s Office, 320 W. Fourth St., Suite 500, Los Angeles, CA 90013, submitted at the CPUC’s website at www.cpuc.ca.gov/909areacode, emailed to public.advisor@cpuc.ca.gov or by phone at 866-340-6147.

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