R.I. Gen. Laws § 46-25-21: Sewer, user fees, charges, and assessments.

For the purpose of causing the project and its operation, maintenance, and improvements to be self liquidating, the commission shall assess any person having a direct or an indirect connection to the project the reasonable charges for the use, operation, maintenance, and improvements of the project. The sewer user fees, charges, and assessments shall be subject to the approval of the public utilities commission.