If the defendant objects to a taking under Section 1240.510, the defendant has the burden of proof that his property is appropriated to public use. If it is established that the property is appropriated to public use, the plaintiff has the burden of proof that its proposed use satisfies the requirements of Section 1240.510.
Source:
Section 1240.520, https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=CCP§ionNum=1240.520..