PUC § 103390

Subject to any agreement or covenant between the district and the holders of any of its obligations limiting or restricting classes of investments, the district may invest any surplus money in its treasury, including money in any sinking fund, reserve fund, or other fund created or established for the benefit of holders of any outstanding obligations of the district, in any of the following:

(a) Its own bonds.

(b) Treasury notes, certificates of indebtedness, bills, bonds of the United States, or any other evidence of indebtedness secured by the full faith and credit of the United States.

(c) Obligations issued pursuant to the Federal Home Loan Bank Act or the National Housing Act.

(d) Treasury notes or bonds of this state, or of any public corporation, municipal corporation, public district, or political subdivision within this state which are legal as security for the deposit of public funds.

(e) In any investment in which county funds may be placed pursuant to the general laws of the state.