The Los Angeles Times says nearly 69 percent of Santa Clara County voters mail in their ballots, in Marin county it is nearly 60 percent and in San Francisco, 40 percent.
It's also very popular in Alameda County with 46 percent of absentee ballots, and workers are already counting them.
An average of 400 ballots a day are coming in through the mail in Alameda County. The county brought in 100 extra temporary workers for the election.
"It takes a lot of processing when you vote by mail. You sign the envelope and we have to verify all of the signatures, and that takes a lot of time. Once we verify the signatures and we check all of the envelopes, we pull the ballot out and we take the envelope and we pull the ballot out and get it ready for processing. We are staying current with today's mail, so we are on top of it," said Dave Macdonald from the Alameda County Registrar's Office.
About 46 percent of the electorate in Alameda County has requested a ballot by mail, putting the county above the state average at 40 percent.
The registrar said he isn't surprised. He said voting by mail is good for elections because you get a better turnout.
"I'm very much in favor of at some point doing vote by mail, at least for maybe some of the smaller elections," said Macdonald.
It certainly means a lot of work for his staff on the front end. Cris Francisco has been at the Registrar's Office since 1990, and she's never worked quite this hard.
"There are times which I have to take my work at home for my people to get their time sheets. I have to work at home because if I get to do it here, there is no time to time because they always call my name to ask questions. This is a very busy election," said Francisco.
If you want a mail-in ballot you are almost running out of time. If you have any additional questions or concerns, just call your county.