Rhode Island General Laws Title 5. Businesses and Professions § 5-20-2. “Plumbing” and “source of water” defined

(i) All fittings, fixtures, appliances, and connections that are located within a building or a structure, or within five feet (5’) of the outer walls of a building or structure and that connect said building or structure, where a person or persons live, work, or assemble, with the source of public or private water supply used or intended for domestic or personal use, as well as any interconnecting piping between buildings or structures;

(ii) All piping, fittings, fixtures, and appliances for a sanitary drainage and related ventilation system, direct or indirect, within that building; and

(iii) Air piping, medical, and laboratory gas systems including, but not limited to, oxygen and nitrous oxide.