After the Washington State Department of Health said they would rely on the honor system to only vaccinate people who live or work in the state, they have changed the requirements.
People who register for vaccines at any mass vaccination site may be asked to provide one of the following:
Driver’s license or work/school ID, Letter with your address,Utility bill,Statement/letter with a Washington state address, or Voucher from an employer, faith-based institution, health care provider, school, or other registered organization or agency, etc. that the person lives or works in Washington state.
The vaccine site will not make a copy or record this information in any way. This is only to show that the person currently resides or works in Washington state.