As stated In City’s ACT 167 Stormwater Management Plan, impervious area is defined as follows:
“A surface that prevents the infiltration of water into the ground; impervious surfaces include but are not limited to roofs, additional indoor living spaces, patios, garages, storage sheds, and similar structures, parking or driveway areas, and any new streets and sidewalks. Any surface areas proposed to initially be gravel or crushed stone shall be assumed to be impervious surfaces.”
Determining the actual impervious area of each property for billing purposes would’ve increased the cost of implementing the program, so city officials and the Bradford Sanitary Authority decided to minimize costs for city residents by using an average instead. All residential properties will equate to one Equivalent Run-off Unit (ERU) and are assessed a flat rate. Larger commercial and industrial properties will be defined in multiple ERU units based on one thousand square foot units of impervious area.