Cal. Sts. & High. Code § 5301

If a lot or parcel of land belonging to the United States, or to the state, or to a county, city, public agent, mandatory of the government, school board, educational, penal or reform institution, or facility for the housing of persons with developmental or intellectual disabilities or mental health disorders is in use in the performance of a public function, and is included within the district to be assessed to pay the costs and expenses thereof, the legislative body may, in the resolution of intention, declare that the lots or parcels of land, or any of them, shall be omitted from the assessment thereafter to be made to cover the costs and expenses of the work.