Any action or proceeding wherein the validity of the adoption of the extension, expansion, or increase of the retail transactions and use tax, or the issuance of any bonds thereunder, or any of the proceedings in relation thereto is contested, questioned, or denied, shall be commenced within 60 days from the date of the election at which the ordinance is approved; otherwise, the bonds and all proceedings in relation thereto, including the adoption and approval of the ordinance and the levy and collection of the retail transactions and use tax, shall be held to be valid and in every respect legal and incontestable.
Source:
Section 132330, https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=PUC§ionNum=132330..