The amount of impervious surface (hard surfaces like roads, buildings, driveways and parking lots), and land use type are the factors taken into consideration to determine an equitable fee. As we build more impervious surfaces, the amount of stormwater that runs off the land without soaking into the ground increases. As the percentage of impervious area on property increases, our surface waters slowly become more polluted, aquatic habitats deteriorate, and flooding risks increase. The percent of impervious area on a parcel can be measured on aerial photographs or calculated by a licensed professional from site and general development plans. Additionally, we know that as the percent of impervious area increases, other factors, like land use and development density, also impact our storm sewer system and surface waters by increasing runoff rates, runoff volumes, and pollutant loads. The fee is determined as follows:
Single-Family Residential Fee
The flat annual fee for each single-family residential parcel is $39.83. The County has found that, irrespective of the size of a residential parcel, the amount of stormwater runoff and pollutant loading from residential development is similar and that it would be excessively and unnecessarily expensive to determine precisely the percent impervious area for each of the 46,000+ residential parcels in Henry County. Therefore, each residential parcel in the County will be charged a uniform residential fee of $39.83, regardless of the size of each parcel or the amount of impervious area on each parcel. Based on a statistical sampling and for the purpose of calculating the Fee, all residential parcels are considered to contain 4,780 square feet of impervious area.
The same equation is used to calculate the Fee for non-residential parcels. However, the impervious area on non-residential parcels varies significatly, so in this case, the amount of impervious area for each parcel was actually measured using a combination of aerial photography and tax assessor’s data. The Non Single-Family Residential Fee (commercial, industrial, institutional businesses) is $39.83 for every 4,780 square feet of impervious surface. For example, a grocery store that contains exactly 15 times the impervious area of the average sized house (15 x 4,780 = 71,700 square feet) will pay 15 times the single-family rate or $597.45 per year.