The letterhead or other prominent location on official stationery of each state agency, and county, city, including, but not limited to, a chartered city, and each school district, municipal corporation, district, political subdivision, and board, commission, and agency thereof, and every other local public agency, used in communication with the public, shall include the telephone number of such entity. The telephone number may be typed or handwritten on the letterhead or other prominent location.
Ca. Gov. Code § 7525