The impervious cover data was generated using aerial photography collected in January 2015. Each pixel on the aerial photography represents 6 inches on the ground. The accuracy is suitable for defining the edges of buildings, patios, driveways and other types of impervious cover. This data was used to create impervious cover maps seen on the Find My Drainage Charge Map Tool. (For best results, use Internet Explorer 9 or higher, Firefox, Google Chrome or Safari.)

For properties developed or modified after January 2015, we use building permit data. Aerial photography for 2017 has already been taken, and a project is currently underway to update the impervious cover maps based on the 2017 photography. Bills will be adjusted based on the updated impervious cover information in February 2019.