Early returns show Lt. Gov. John Garamendi, 64 and a Democrat, leading in his bid for the 10th Congressional District seat, with 57,002 votes, or 53.45 percent of the votes cast, over his GOP opponent David Harmer, who has 44,844 votes, or 42.05 percent.
The results were posted at 11 p.m. with 188 of 273 precincts reported.
At the same time, San Ramon voters have reelected Mayor Abram Wilson and City Councilmen David Hudson and Jim Livingstone.
With all 11 precincts reported, Hudson received 4,923 votes, or 37.91 percent of the votes cast, and Livingstone received 4,191 votes, or 32.27 percent. Trailing were Jim Brady, with 2,348 votes, or 18.08 percent, and Doug Burr with 1,470 votes, or 11.32 percent.
Wilson, who ran unopposed, received 6,276 votes, or 95.8 percent of the votes cast.
With all 26 precincts reported, the measure that would allow construction of a Neiman-Marcus store in downtown Walnut Creek was approved by 71.4 percent of the voters, garnering 15,280 favorable votes to 6,111 opposed.
Voters also approved school measures in the Acalanes Union High School District and the Walnut Creek School District to make permanent the parcel taxes in both districts.
The Garamendi-Harmer race was being watched nationally to see if a Democrat would succeed long-time Democratic Congresswoman Tauscher, who resigned the post to become the State Department's undersecretary for arms control and international security affairs.
Garamendi's victory was no surprise. A recent public poll showed Harmer trailing Garamendi by double digits in a district where Democrats make up 47 percent of registered voters compared with 29 percent that are registered as Republicans.
The 10th Congressional District includes Livermore, much of Contra Costa County, as well as parts of Alameda, Solano and Sacramento counties.