Cal. Rev. & Tax. Code § 259.14

(a) The claim for welfare exemption on qualified property, in addition to giving any other information as prescribed by the board, shall be accompanied by an affidavit that provides both of the following:
1. (1) A list of units occupied by lower income households for which the exemption is claimed.
2. (2) All of the following nonpersonally identifiable information about the occupants of the units listed pursuant to paragraph (1):
  1. (A) The actual household income of the occupant.
  2. (B) The maximum rent that may be charged to the occupant.
  3. (C) The actual rent charged to the occupant.
(b) The affidavit required to accompany the claim for welfare exemption pursuant to subdivision (a) shall be confidential and shall not be subject to public disclosure.
(c) For purposes of this section, “qualified property” has the same meaning as that term is defined in Section 214.17.