The storm water fee is based on the number of SFUs attributed to the property. The term SFU is an acronym for Single Family Unit and is the amount of impervious area (hard surfaces) associated with an average single family home. Impervious area includes pavement, compacted gravel and building footprints. Examples include driveways, parking areas, rooftops and patios. The amount of impervious area on a property directly correlates to its contribution of runoff volume and pollutant loading to the City’s storm water management system. In the City of Memphis, the average SFU was determined to be 3,147 square feet. This value represents one SFU and has been statistically determined to represent the average impervious area for residential customers in the City. As of July 1, 2010 the storm water fee assessed to each SFU is $4.02.
Single family homes are divided into one of three classifications: small, average, and large. The rates are based on the total impervious area associated with each classification. An average home is assessed one SFU, a small home is assessed 58% of one SFU, and a large home is assessed 152% of one SFU.
Multifamily residents are divided into one of four classifications: multifamily, town home/condominium, mobile home, and high rise apartments. The rate charged to each residential unit is based on the average impervious area associated with the building classification. A multifamily unit is assessed 41% of one SFU, a town home/condominium is assessed 57% of one SFU, a mobile home is assessed 77% of one SFU, and a high rise apartment is assessed 13% of one SFU.
Nonresidential property is defined as parcels used for commercial, industrial, governmental, institutional, and agricultural use. The storm water fee for these properties is based on the number of SFUs associated with the property. The total SFU count is determined by dividing the impervious area by 3,147 square feet. The monthly rate would then be the number of SFUs times the current base rate ($4.02 per SFU as of July 1, 2010).