Units of impervious area.

A. The drainage charge shall be based on the number of units of impervious area which the site or building for which the permit is sought shall contain after it is fully constructed and developed in accordance with plans approved by and filed with the town.

B. Units of impervious area shall be assigned as follows:

(1) Single- and two-family residential dwellings: one unit.

(2) All other developments: one unit for each 3,500 square feet of impervious area within the development, excluding dedicated roads, but in no event less than one unit. The number of square feet shall be determined by the Town Engineer.