12 CFR §229.42

The expeditious return (§§ 229.31(b) and 229.32(b)), notice of nonpayment (§ 229.31(c)), and same-day settlement (§ 229.36(d)) requirements of this subpart do not apply to a check drawn upon the United States Treasury, to a U.S. Postal Service money order, or to a check drawn on a state or a unit of general local government that is not payable through or at a bank.