If any interest in real property is to be acquired by exercise of the power of eminent domain, the public entity shall institute formal condemnation proceedings. No public entity shall intentionally make it necessary for an owner to institute legal proceedings to prove the fact of the taking of his real property.
Source:
Section 7267.6, https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=GOV§ionNum=7267.6..