R.I. Gen. Laws § 44-5-20.10: Johnston — Property tax classification authorized.

The town of Johnston may, by resolution or ordinance adopted by the town council, provide for a system of classification of taxable property as follows:

(1) Class one: all residential real estate that consists of not more than five (5) dwelling units;

(2) Class two: all commercial and industrial real estate and all residential real estate that consists of six (6) or more dwelling units;

(3) Class three: all ratable tangible personal property; and

(4) Class four: all motor vehicles and trailers subject to the excise tax created by chapter 34 of this title.