Workers have started demolishing a five-story building that most recently housed the county tax collector's office, among others.

The demolition will clear the way for San Joaquin County to build a $108 million headquarters of 250,000 square feet by 2009 on property east of the County Courthouse. That property was bought from Stockton recently for $1.

The existing seven-story Courthouse contains court facilities as well as offices for the five elected county supervisors, county administrators and attorneys, and various departments, including the Office of Emergency Services and the district attorney. Other county workers use a half-dozen other buildings downtown.

In the new eight-story administration building, county residents will be able to register to vote, pay taxes, apply for a marriage license and visit their local supervisor in one location.

The county intends to pay off a $100 million loan to fund the project using proceeds from a developer fee adopted in 2005.

The state also wants to begin work on a $232million, 283,000-square-foot Superior Court building just west of the existing Courthouse by 2010. That eight-story building, to be built where Hunter Square Plaza sits, would have 30 courtrooms. The existing Courthouse has 22 courtrooms.