R.I. Gen. Laws § 46-13-7: Tanks connected to unsafe supplies.

Any person who maintains a public water supply system connection to a tank which is also supplied with water from a water supply system found by the director to be unsafe, shall maintain the tank open to atmospheric pressure, and the public water supply pipe shall terminate at least two (2) pipe diameters above the maximum level of water in the tank. The tank overflow shall be of adequate size to fix definitely the maximum level.