The following information pertains specifically to the calculation and application of impervious cover for determining the drainage charge imposed by the City of Austin's Watershed Protection Department.
Impervious cover is any type of human-made surface that doesn’t absorb rainfall, including:
- Rooftops
- Patios
- Driveways, paved and unpaved
- Sidewalks
- Roadways
- Parking lots, paved and unpaved
- Some decks
Uncovered wooden decks and unpaved portions of driveways count as 50% impervious cover. If you have these features, we may be able to lower the impervious cover on your account, which will in turn lower your bill. Please call 512-494-9400 and ask about an administrative review of your drainage charge.
A more complete definition of impervious cover is found in Section 25-8-63 of the Austin City Code. While impervious cover has broader implications in terms of urban planning and land development regulations, this information focuses on its connection to the drainage charge. For more comprehensive information about impervious cover regulations beyond the drainage charge, please refer to the appropriate resources and guidelines provided by the City's Development Services Department.