Austinites citywide may see an increase or decrease in their drainage bills, according to the Watershed Protection Department.
The department said in 70 percent of cases, the data update will result in no change or a change of less than $1. In 30 percent of cases, however, there could be a larger increase or decrease beginning with July utility bills. The department said no specific area of the city should expect to be targeted by this change.
The change in the drainage charge results from updated flyover data collected by the city. The data was previously based on aerial images taken in 2012 and submitted building permits. Now the city will use updated images created with a new flyover system that more accurately maps impervious cover, according to the department.
For example, the mapping can now track impervious cover blocked by tree coverage in photographs.
The city calculates the drainage charge by measuring a property's impervious cover, which is any type of covering that doesn’t easily absorb rainfall. Types of impervious cover include rooftops, driveways and parking lots. Austin property owners can calculate their impervious cover using the city’s “Find My Drainage” tool.
A few factors could change a resident's drainage fee, said Anupa Gharpurey, financial manager for the Watershed Protection Department. The property may not have been previously permitted or the building footprint may not have included the roofing footage. Owners of properties that have been recently renovated or subdivided with new construction may also see a larger change in their bill.
The drainage charge pays for projects that maintain water systems to reduce the effect of flooding, erosion and water pollution, Gharpurey said.
“The charges go toward maintaining and improving the stormwater infrastructure,” she said. “This charge helps make Austin a safer and cleaner city.”