Ballots are received, sorted and verified at the Los Angeles County ballot processing facility in Industry, California, on November 9, 2022.
CNN  — 

Even after CNN projected on Wednesday that Republicans will win the House majority, five House races in California remained uncalled. That raises a perennial question: Why does it take California so long to count its votes?

More than a week after Election Day, attention turned to some of the outstanding races in California. Tuesday was the last day that county election officials could accept ballots that were postmarked on or before Election Day – meaning the Golden State is just getting started counting some of those late-arriving ballots.

California now mails every registered voter a ballot, a practice that began in 2020 amid the Covid-19 pandemic and ultimately became permanent in September 2021 in an effort to increase voter access and participation. Under state law, ballots postmarked on or before Election Day must be accepted by county elections offices for seven days after polls close.

The sheer volume of ballots that election officials are now counting is enormous. In the 2020 election, more than 15 million mail ballots were cast in the general election – comprising about 87% of the total. This year, there were nearly 22 million registered California voters by mid-October, according to figures from the California secretary of state.

The official canvassing period – the process of tabulating votes – will continue up to December 8, when county election officials must report their final official results to the secretary of state (though some counties have set earlier deadlines to certify their own election results). The California secretary of state will certify the state’s results by December 16.

“It’s just a huge electorate and in some of the counties – LA County, Orange County, even Kern County where the [GOP Rep. David] Valadao race is – there are a lot of people living there and a lot of ballots that have to be counted,” said Christian Grose, academic director at the USC Schwarzenegger Institute for State and Global Policy, who has studied election administration. “With that ‘week after’ deadline, really the counting starts in earnest now. They really will be finishing the counting in the next week or two instead of the immediate day after Election Day.”

The resources available to count ballots also vary widely by jurisdiction. In Kern County, where Valadao is defending his seat in a close contest with Democratic state Assemblyman Rudy Salas, Grose noted, “They only have one ballot counting machine. That’s a funding and resource choice. They should probably have more than one ballot counting machine.”

The counting took so long in Valadao’s 2018 race against Democrat TJ Cox that it was the last uncalled House race in the country. Cox narrowly unseated Valadao that year before the Republican won a rematch in 2020. (This cycle, Kern County Clerk Mary Bedard told KGET in Bakersfield that it could take weeks to count the remaining 70,000 ballots in that county, in part because the county has just one sorter machine).

The processing of each mail ballot in California is labor intensive, in part because there are many safeguards built into the process. Once county election officials receive the ballots, they must confirm that the voter has not already voted, verify their signature on the ballot envelope, remove the ballot from the return envelope, then tally the votes. There are also additional tranches of ballots that take even more time to process, including provisional ballots, ballots from voters who took advantage of same-day voter registration and damaged ballots that couldn’t be read by machines.

As of Tuesday evening, there were more than 2.8 million ballots remaining to be counted statewide, according to the secretary of state’s latest unprocessed ballots report. The secretary of state’s office did not respond to a request for an interview this week about the speed of the process. But California Secretary of State Shirley N. Weber released a statement on Tuesday night stating that it could take days or weeks to know the final results of a number of close contests.

“We have a huge population of registered voters and California stresses enfranchisement, so we have a process that by law ensures both voting rights and the integrity of elections,” Weber said in a statement. “I would call on all everyone to be patient.”

In Los Angeles County, there were about 565,000 outstanding ballots as of Tuesday. The Los Angeles County Registrar-Recorder/County Clerk does not provide information about how many ballots remain by jurisdiction, leaving the mayoral campaigns in the dark about how many of those ballots will determine the city mayoral election or even which parts of the city they are from. (There are 88 cities in LA County and a spokesman for the Los Angeles County registrar’s office noted that if they were to take the extra step of organizing ballots by jurisdiction, that could prolong the tallying process).

When asked about the lengthy processing times for counting ballots in Los Angeles County, Mike Sanchez, a spokesman for the Los Angeles County registrar, said the priority is to ensure that all eligible ballots cast by Election Day and returned through the postal service (or left in person at a ballot drop box or vote center) “are processed, verified, and counted – and this takes time.”

“In California, counties have 30 days to process these ballots – which in Los Angeles County can be hundreds of thousands – and to certify election results,” he said. “This 30-day period and its activities and timelines are consistent to past election cycles, including the 2020 presidential election.”

California’s nonpartisan redistricting process also created more competitive districts than in many other states, resulting in tight races – particularly in Orange County, a former Republican bastion-turned-battleground where President Joe Biden made a final campaign swing to help Democratic Rep. Katie Porter. CNN still has not projected a winner in Porter’s race or several other House contests in California (including one between two Democrats), as well as several other House races in Alaska, Colorado, Maine and Oregon.

This story has been updated on Wednesday with additional developments.