Pub. Util. Code, § 13123

Money in any such reserve fund shall be drawn therefrom only upon demands authenticated by the signature of the accountant of the district; provided, however, that the board may, in its discretion, direct and authorize the payment from such reserve fund, by the treasurer, without such authenticated demand, (i) of bonds of the issue in connection with which such reserve fund is so established when due upon maturity or call, or of coupons pertaining to bonds of such issue when due, but only upon presentation and surrender of such bonds or coupons, (ii) of interest upon registered bonds of such issue when due, or (iii) of premiums, if any, due upon the redemption of any such bonds.