Cal. Health and Safety Code § 17961

(a) The housing or building department or, if there is no building department acting pursuant to this section, the health department of every city, county, or city and county, or any environmental agency authorized pursuant to Section 101275, shall enforce within its jurisdiction all of this part, the building standards published in the State Building Standards Code, and the other rules and regulations adopted pursuant to this part pertaining to the maintenance, sanitation, ventilation, use, or occupancy of apartment houses, hotels, or dwellings. The health department or the environmental agency may, in conjunction with a local housing or building department acting pursuant to this section, enforce within its jurisdiction all of this part, the building standards published in the State Building Standards Code, and the other rules and regulations adopted pursuant to this part pertaining to the maintenance, sanitation, ventilation, use, or occupancy of apartment houses, hotels, or dwellings. Each department and agency, as applicable, shall coordinate enforcement activities with each other and interested departments and agencies in order to avoid unnecessary duplication. (b) Notwithstanding subdivision (a), the health department of every city, county, or city and county, or any environmental agency authorized pursuant to Section 101275 may, in addition to the local building or housing department, if any, enforce within its jurisdiction the provisions of Section 17920.10 and shall coordinate enforcement activities with other interested departments and agencies in order to avoid unnecessary duplication. (c) The State Department of Public Health may enforce Section 17920.10 if any local agency or department specified in subdivisions (a) and (b) enters into a written agreement, approved and published pursuant to local government procedures, with the State Department of Public Health to enforce that section, or provides the State Department of Public Health with a written request to enforce that section for a specific case following the identification of a lead poisoned child in that jurisdiction.