A. Three thousand square feet of impervious ground cover shall be equal to one impervious surface unit (ISU).

B. Each parcel of developed single-family residential property is deemed to contain one equivalent ISU.

1. Single-family residential parcels that contain an additional structure that is equal to or exceeds 3,000 square feet of impervious ground cover will be assessed an additional service charge for each such structure (as defined in BIMC 18.36.030).

C. Other developed property parcels will be assessed utility service charges in accordance with subsection D of this section.

1. Other developed property parcels within mixed-use condominium properties that include both residential and nonresidential properties will be deemed to contain one equivalent ISU per condominium unit.

D. The utility shall determine the actual number of ISUs contained on multifamily and other developed property parcels, and these accounts shall pay a service charge to be calculated as follows: actual impervious ground cover/3,000 square feet x single-family service charge. In making the calculation, fractions shall be rounded to the nearest whole number but not less than one ISU per developed property. (Ord. 2015-20 § 2, 2015)