California Code, Government Code - GOV § 26529

(a) In counties that have a county counsel, the county counsel shall discharge all the duties vested in the district attorney by Sections 26520, 26522, 26523, and 26526. The county counsel shall defend or prosecute all civil actions and proceedings in which the county or any of its officers is concerned or is a party in the officer's official capacity. Except where the county provides other counsel, the county counsel shall defend as provided in Part 7 (commencing with Section 995) of Division 3.6 of Title 1 any action or proceeding brought against an officer, employee, or servant of the county.

(b) Notwithstanding any other provision of law, the County Counsel of the County of Solano may, and when directed by the board of supervisors of that county shall, bring a civil action when the county, or any of its officers, has a cause of action to abate a public nuisance in the county. The County Counsel and the District Attorney of Solano County have the concurrent right to bring an action to abate a public nuisance pursuant to this subdivision.