Cal. Pub. Util. Code § 13191

Pending use for the purposes for which any reserve fund or special trust account or any other separate fund established pursuant to this chapter was so established, money set aside and placed therein may, when and to such extent and in such manner as may be directed by the said board and as may be consistent with the provisions of any resolutions of the board constituting a part of the proceedings for the issuance of the issue of bonds in connection with which such fund or account was created, be invested in the same manner as are other moneys of the district. Any such bonds or other evidences of indebtedness acquired through such investment may be resold at any time.