California Code, Government Code - GOV § 56100.1

(a) Contributions and expenditures for political purposes related to a proposal or proceeding shall be disclosed and reported pursuant to Article 2.5 (commencing with Section 84250) of Chapter 4 of the Political Reform Act of 1974 (Title 9 (commencing with Section 81000)).

(b) A commission may require, through the adoption of written policies and procedures, additional disclosure of contributions in support of or opposition to a proposal, which shall be made either to the commission's executive officer, in which case it shall be posted on the commission's Internet Web site, if applicable, or to the board of supervisors of the county in which the commission is located, which may designate a county officer to receive the disclosure.  Disclosure pursuant to a requirement under the authority provided in this section shall be in addition to any disclosure otherwise required by Section 56700.1, 57009, or local ordinance.