DANVILLE (KCBS/AP) The Bay Area’s only competitive congressional race remained too close to call Wednesday, with Democratic incumbent Jerry McNerney barely leading Republican challenger David Harmer in the battle for the East Bay’s 11th Congressional District.

A deluge of absentee ballots that were dropped off at polling stations on Election Day is delaying results of a race where the candidates are separated by less than two dozen votes.

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San Ramon attorney David Harmer maintained a slight advantage Wednesday over two-term Democratic Rep. Jerry McNerney. With 99 percent of precincts reporting, Harmer was leading by 23 votes out of more than 172,000 ballots cast in Northern California’s 11th District.

KCBS’ Margie Shafer Reports:

The race remained too close to call, and its four counties reported that hundreds of thousands of last-minute vote-by-mail and provisional ballots still must be processed. Officials don’t yet know how many of those are from constituents of the 11th District, which extends from the eastern San Francisco Bay area suburbs into the San Joaquin Valley.

KCBS’ Tim Ryan Reports:

“The vote-by-mail drop-offs at polling places were very, very heavy,” said Dave MacDonald, the registrar in Alameda County, which makes up the smallest share of the district. “I don’t think any of us have ever seen that volume. We’re still just trying to figure out what we have.”

MacDonald did not yet have an estimate of how many ballots came in Tuesday, but by that morning, the county had only received 42 percent of the absentee ballots it had mailed to voters.

In Santa Clara County, an estimated 135,000 vote-by-mail and 18,000 provisional ballots were turned in Tuesday, said registrar spokeswoman Elma Rosas. More than 22,000 registered voters in the county are part of the 11th District, she said.

The county hopes to have about 100,000 absentee ballots processed by Friday afternoon, and the rest by the end of the day Monday, Rosas said. Officials then will begin counting the provisional ballots, she said.

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The 11th District also includes portions of Contra Costa and San Joaquin counties. Contra Costa County Registrar Steve Weir estimated his office could have as many as 100,000 vote-by-mail ballots left to count.

The San Joaquin County registrar’s office did not immediately respond to requests for comment Wednesday.

Both campaigns expressed optimism about the outcome, but said they didn’t expect a final tally any time soon.

“We have teams deployed at every county registrar’s office—so does the other side—and we’re in that wait-and-see period,” said Harmer campaign spokeswoman Melissa Subbotin. “It’s far too premature at this point to make any kind of prediction.”

The 11th District was one of five hotly contested congressional races throughout California this year—a relatively high number in a state where congressional elections generally offer little excitement.

Incumbents in three of the competitive races held their seats—
Democrat Loretta Sanchez in Orange County, and Republicans Mary Bono Mack in Riverside County and Dan Lungren in the Sacramento area. Another race, in the Central Valley, also remained too close to call Wednesday.

That contest pitted Rep. Jim Costa, a conservative Democrat, against Hanford farmer Andy Vidak in the agriculture-dominated 20th District.

Both candidates saw a sudden surge of attention and donations over the past month. Republicans hoped voter frustration in the economically hard-hit region would help them overcome Democrats’ 20-point voter registration advantage.

Vidak was leading by just over 1 percent—or 693 votes—with all precincts reporting.

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