Cal. Rev. & Tax. Code § 213.5
In partial consideration of the public services provided to property exempted from taxation by Section 214, the owner or person in possession shall permit the free use of such property or portion thereof as a polling place at any election conducted by the registrar of voters if the registrar makes written request for the use of such property at least 60 days before the date of the election. The registrar shall not be entitled to the use of any property used for the practice of religion if the owner or possessor files with him at least 45 days before the election an affidavit that (a) the space requested will be required for the ordinary and usual purposes of the owner or possessor on the day of the election, setting forth what such use will be, or (b) by reason of any contract, or condition, or covenant in a deed, made or delivered before July 1, 1965, the use of any portion of such property by the registrar of voters would breach such contract, condition, or covenant. The registrar shall not be entitled to the use of other property if an affidavit under (b) is filed with him.
As used in this section, registrar of voters means county clerk in counties having no registrar of voters.
A county using this section shall insure itself, its employees, the owner, and the person in possession of the property against any liability for any injury connected with the use of the property as a polling place.
Use of property under this section shall be considered to be exclusively for religious, hospital, or charitable purposes.
Ca. Rev. and Tax. Code § 213.5