SAN FRANCISCO (KGO) -- Starting this Saturday, people dialing from a 415 phone number to another 415 number will have to dial 1 plus 415, as if they were calling another area code.
People who don't remember to dial 1 before punching in the area code will hear a recording telling them their call did not go through and to hang up and dial again.
The change is happening so the California Public Utilities Commission can introduce a new area code.
The new 628 code will be an overlay, meaning it will be assigned to new numbers in the 415 region.
Phone numbers a 628 area code will start being assigned next month, but the dialing change starts Saturday.