Sonoma County uses the Dominion Voting Systems paper ballot optical scan voting system. This voting system has been certified for use in California by the Secretary of State. Using paper ballots, voters fill in ovals next to their choice.
Ballots are transported to the secure, Sonoma County Ballot Counting Room, where they are tabulated on the Dominion ImageCast Central central count scanner. With this system, you can have confidence that your vote is counted accurately and reliably.
Read about California Election Security