Gov. Code, § 50054

Whenever any city or county or city and county renders construction services or constructs public works for any city, county, city and county or any other governmental agency below the level of the state government, the price charged for such services or construction shall be sufficient to reimburse the governmental body performing such services for the full cost thereof including labor, material, equipment costs or rentals and a reasonable allowance for overhead. In computing overhead, without limitation on other factors properly includable, there shall be allocated to the overhead cost its proportionate share of indirect labor and administrative costs.