If you make changes to impervious cover on your property, expect your drainage charge to change. However, there may be a lag time before changes are reflected in your charge. Changes that may affect your charge include increasing your parking, building an addition or adding a deck or shed. Removing impervious cover will reduce your charge. If you have removed impervious cover, please call 512-494-9400 to let us know, so we can adjust your charge for you sooner.