Iowa Admin. Code r. 875-217.27
Payments of the prescribed wages shall be in currency or negotiable instrument payable at par. Although these rules provide for the inclusion in the "wage" paid to any employee, under the conditions which it prescribes of the "reasonable cost," or "fair value" of furnishing the employee with board, lodging, or other facilities, the employer can only include the furnishing of facilities as a portion of the prescribed wage if the employee has agreed in writing prior to the period of employment for which payment will be made to receive payment in a form other than currency or negotiable instrument payable at par. In addition, a tipped employee's wages may consist in part of tips. These rules permit and govern the payment of wages in other than cash.
Iowa Admin. Code r. 875-217.27
29 CFR 531.27.