R.I. Gen. Laws § 5-56-1: License required.

(a) It is unlawful for any person to install, construct, alter, or repair, or cause to be installed, constructed, altered, or repaired, any individual sewage disposal system unless he or she has a valid annual license issued by the director of environmental management.

(b) This section does not apply to a property owner installing, constructing, altering, or repairing an individual sewage disposal system to serve a building he or she occupies or will occupy as his or her intended permanent domicile; provided, that he or she has obtained written permission for that work, and that he or she has obtained the necessary written approval of the director of the plans and specifications for that work prior to the start of any construction.