Equivalent Residential Units (ERUs) are used to assess the Stormwater Utility. It was determined that the average residential lot has a total of 2,900 square feet of impervious surfaces. An impervious surface is any surface that prevents water from penetrating the ground. Examples include buildings, driveways, parking lots, concrete surfaces, paved areas, gravel areas, tanks and any other features that do not allow rainfall to soak into the ground. The average square footage of impervious surface area is known as an equivalent residential unit.
Each residential property within the Town is charged for one ERU per month at a pre-defined rate. Non-residential properties are also charged based on the amount of impervious surface on their property. The total amount of impervious surface area on a non-residential parcel of land is divided by 2900 square feet (one ERU) to determine the number of ERU’s associated with a given parcel. These properties are then charged a pre-defined rate per ERU per month. For example, a commercial property with 11,600 square feet of impervious area would be charged for 4 ERUs (11,600 square feet / 2,900 square feet) and would pay a monthly stormwater utility fee of four times the residential rate.
The Town’s authority for collecting the Stormwater Utility is found in Chapter 56 of the Town of Brownsburg’s Code of Ordinances and Indiana Code 36-9-23.