Beginning with November 2015 bills, the method of calculating the drainage charge has been revised to:
Be calculated the same way for all properties and eliminate the distinction between commercial, residential and high-rise residential properties.
Be calculated for each property based on the amount and percentage of impervious cover. Impervious cover includes rooftops, patios, driveways, parking lots and other surfaces that do not absorb rainfall.
Take into account the impact of each property's improvements on the City’s stormwater drainage system. The drainage system includes more than 900 miles of creeks, channels, ditches, pipes, dams and stormwater ponds.
The City has adopted administrative rules for the drainage charge. These rules guide staff in interpreting the drainage charge ordinance (Chapter 15-2 of the Austin City Code). Relevant documents and links are below: