What is impervious cover?
Impervious cover refers to any man made surfaces, like asphalt, concrete, and rooftops, that water cannot penetrate. With these surfaces rain and snow that would otherwise soak into the ground turns into stormwater runoff when it comes into contact with impervious surfaces.

The Falls Church stormwater utility fee further defines impervious cover as:
  • Asphalt driveways / walkways
  • Compacted soil with no vegetation
  • Compacted stone driveways
  • Concrete driveways / walkways / stairs / patios
  • Decks over concrete slabs (decks over uncompacted stone are considered pervious)
  • Garages
  • Pools and concrete pool decks
  • Porous pavers (paver systems are open to a credit discount)
  • Rooftops of homes
  • Sheds / storage containers

Show All Answers

1. What is impervious cover?
2. How does impervious cover impact volume of stormwater runoff?
3. Why is stormwater runoff polluted?
4. What can I do to reduce my impact on stormwater runoff?
5. Where can I find more information about stormwater?