Fees are assessed according to the impervious surface area or Stormwater “footprint” of each parcel, rather than property value. Each parcel will be billed for each equivalent resident unit (“ERU”). Equivalent residential unit means 3,000 square feet of impervious surface. Each ERU is billed at a rate of $5.00 per month. Residentially zoned property, excluding multi-family housing, is billed one (1) ERU (ex. $5.00 per month). For non-residentially zoned property, including multi-family housing, the number of ERUs to be billed is calculated by taking the square footage of the property and multiplying the square footage by Seventy-five percent (75%) and then dividing by 3,000 (ex. 5 acre parcel – 43,560 x 5 = 217,800; 217,800 x 75% = 163,350; 163,350 / 3000 = 54.45 ERUs; 54.45 x $5.00 = $272.25 per month).