"But I mean, there's so many checks and balances that goes into the process that, I don't want to say impossible because anything's possible, but it's damn near impossible," Hammergren said.
Still, he gets calls from people who hear news stories about voter fraud. He tells them you can monitor us.
"You want to see it happen? Come down, you can watch us check and balance, check signatures. You can watch us how we extract them, how we sort them, how we scan them," Hammergren said.
One thing election officials dislike is trying out new systems in a presidential election, where the stakes are higher and everyone is watching. Inyo County Clerk-Recorder Kammi Foote says the board of supervisors keeps asking her how the November election will be different from typical elections.
"And I have to say, we're planning for every single difference," Foote said. "Every different method I could possibly think of because we have executive orders. We have legal challenges, we have legislation in different parts of the process. So I don't actually really know yet."
Kim Alexander, president of the California Voter Foundation, says when it comes to mail-in ballots, it’s not fraud that concerns her — it’s the thousands of valid ballots that might be tossed out because a voter forgets to sign a ballot or the signature doesn't match what's on file — or they mail it late.
Still, she strongly supports voting by mail.
"Is it going to be perfect? No. But voters should be able to feel confident going into this election that if they follow the instructions and they get their ballots in on time, their ballots are going to be counted and their votes are going to count," Alexander said.