RSA 485:42 Variances and Exemptions.

I. The department may, after notice and opportunity for hearing, grant one or more variances from an applicable state drinking water regulation to a public water system if the variance will not result in an unreasonable risk to the public health, and if:
(a) Because of the characteristics of the raw water sources reasonably available to the system, the system cannot meet the maximum contaminant levels of such drinking water regulation despite application of the best available technology, treatment techniques or other means. The department's finding of the best available technology treatment, treatment technique or other means may vary depending upon the number of persons served by the system or for other physical conditions related to engineering feasibility and cost of compli