R.I. Gen. Laws § 46-13-19: Variances and exemptions.

The director may authorize variances or exemptions from the regulations adopted pursuant to this chapter under conditions and in such manner as he or she deems necessary and desirable; provided, however, that the variances or exemptions are permitted under conditions and in a manner which is not less stringent than the conditions under, and the manner in which, variances and exemptions may be granted under the federal Safe Drinking Water Act, P.L. 93-523, and any amendments thereto, 42 U.S.C. § 300f et seq.