10 digit dialing will become mandatory for all local calls on September 30, 2017.
The Western Washington area has seen much growth and as a result additional phone numbers are necessary for other providers. The new area code 564 will be launched over the entire area in 2018 to create more numbers. 10 digit local dialing is already functional for all HCC subscribers today.
You can get ready now by updating your speed dial entries on your smartphone, landline phones, fax machines, etc.