What is an impervious surface?

Impervious surfaces are those areas within developed land that prevent or significantly impede the natural infiltration of stormwater into the soil. Common impervious surfaces include:

  • Asphalt streets
  • Brick or concrete pavers
  • Buildings
  • Compacted gravel surfaces
  • Decks
  • Driveways
  • Parking areas
  • Patios
  • Rooftops
  • Sidewalks

Show All Answers

1. Where can I find information on the Stormwater Master Plan? How can I provide input to this study?
2. What is Low Impact Development?
3. Do I still have to provide stormwater detention if I’m using LID to reduce runoff?
4. How can I apply to receive a utility fee credit for certain measures?
5. What do stormwater staff members do?
6. How are stormwater funds used?
7. When did the stormwater utility fee go in to effect?
8. What is an impervious surface?
9. How is the amount of impervious area calculated?
10. How can I determine how much my stormwater utility fee will cost each month?
11. If the runoff on my property goes directly into the ground and does not affect the city's stormwater system, why do I have to pay?
12. What is an ERU?
13. Do gravel driveways count as impervious areas?
14. Are city sidewalks included in the impervious area calculation for my property?
15. Where can I learn more about Stormwater management, rates and credits?