The City updated its impervious cover and property data that the drainage charge is based on. The City is now using 2015 aerial imagery, current building permit data and current appraisal district data. In general, changes to the charge were more likely if one of the following is true:
You added a patio, deck, driveway, parking, shed, addition or other improvement between 2012 and 2015.
Your address has a lot of trees. The new data better reflects impervious cover hidden by the tree canopy.
Your address was developed between 2012 and 2015. In this case, the previous drainage charge was based on either building permit data or unimproved conditions. It is now based on aerial imagery.
You store vehicles, rock, dirt or other materials on unpaved areas. These open storage areas are considered impervious cover. The new data contains more of these open storage areas than the previous data.
Your address was subdivided or merged with another address since 2015.