Iowa Code § 455B.181
The director may, after public notice and hearing, grant exemptions from a maximum contaminant level or treatment technique, or both. The director may also grant a variance from drinking water standards for public water supply systems when the characteristics of the raw water sources, which are available to a system, cannot meet the requirements with respect to maximum contaminant level of the standards despite application of the best treatment techniques which are generally available and if the director determines that the variance will not result in an unreasonable risk to the public health. A schedule of compliance may be prescribed by the director, at the time the variance or exemption is granted. The director shall also require the interim measures to minimize the contaminant levels of systems subject to the variance or exemption as may reasonably be implemented. The director may also issue variances from other rules of the department if necessary and appropriate. The director shall submit variances granted regarding a wastewater treatment facility to the commission for the commission's review within thirty days of the granting of a variance. The denial of a variance or exemption may be appealed to the commission.
Iowa Code § 455B.181