R.I. Gen. Laws § 45-59-16: Limit on assessments.

The total of the special tax assessments levied on the ratable real property within the management district will not exceed ten percent (10%) of the total of the real property taxes levied on the ratable real property within the management district, not exempt from taxation by law, for the fiscal year of the municipality that ends within or with the fiscal year of the district management authority.