Results released Tuesday are presumed to be close to the final counts, but officials said in a statement on the county Web site that they would continue reviewing ballots until Monday, even though they did not expect any vote totals to change.
"We are taking advantage of this opportunity to review our canvass processes and procedures to enhance quality assurance for the Presidential Primary and General elections in 2012," the statement said.
Officials had promised results this week after taking time to count more than 1,000 provisional ballots cast in the Nov. 8 election.
Many local races were extremely close after Election Day votes were counted due to large numbers of vote mailed in and a low turnout at the polls.
"Given the apparent closeness of some contests, we will certify Monday, Nov. 28, which will provide time for anyone contemplating a recount the opportunity to talk with us," Lindsey McWilliams, the county's assistant registrar, told the Vallejo Times-Herald newspaper.
Presumably final tallies released Tuesday still were classified as unofficial.
"We do not expect vote totals to change between now and Monday," the Web statement said.
Among the closest and most contentious races are in Vallejo, Solano County's largest city; where a proposed 1 percent sales tax increase leads by 159 votes out of more than 18,000 cast, fewer than 1,000 votes separate three candidates for the last City Council seat, and incumbent Osby Davis leads challenger JoAnn Schivley by 1,090 votes in the mayoral race.
Incumbent Erin Hannigan and Bob Sampayan won the other two seats.
In Benicia, incumbent Elizabeth Patterson leads Councilman Alan Schwartzman by 236 votes out of more than 7,000 cast in the race for mayor of Solano County's oldest city.
In Fairfield, the county seat, Rick Vaccaro leads Chuck Timm by only 66 votes in the race for the second of two City Council positions.
Pam Bertani won the other position.