The purpose of the appeals process is to help us accurately calculate your bill If you feel that your bill has been incorrectly calculated or if there is an error with the impervious surface map, please submit an appeal. First, please confirm that the situation does qualify. Please read the examples below as well as the FAQs before submitting an appeal.

Appeal Eligibility

Here are some scenarios that may be approved:

  • A building has been demolished and the area is now grass,
  • The property contains a deck that has open slats and is dirt below.
  • The property contains landscape rock areas that are shown as impervious on the impervious area map.

Here are some scenarios that are not eligible for an appeal:

  • The property contains downspouts draining to the grass.
  • The property is on a private street.
  • The property contains gravel areas.
  • The property contains a detention basin, rain garden, etc. that manages stormwater runoff. Please see our Stormwater Utility Credit Manual to complete a credit application for these best management practices. 

If you have additional questions after reviewing this information, please contact us at 309-494-8800, or email us.

Know Your Surfaces


Decks will display on the map as impervious. If the deck has openings between the boards that allow water to drain to the ground, the city will look at the surface below the deck to make the determination. If the surface below is compacted gravel, concrete, or asphalt, it will be considered impervious. If it is dirt or loose landscape rock, it may be considered previous. Please file an appeal and include photos to have your deck appeal reviewed.

Brick and Gravel

Both brick and gravel are considered impervious surfaces as they are typically not designed for stormwater infiltration.

Surface Runoff

While grass will infiltrate some runoff, in a larger storm, grass areas will also generate stormwater runoff. Grass and other pervious surfaces are not charged in the stormwater utility because they generate a lot less runoff than impervious surfaces. Draining impervious areas to grass or pervious areas does not mean that all of the runoff generated from both surfaces will be soaked into the ground. Runoff will still be generated and leave the property.

Starting the Process

Please explain where specifically on the property the impervious area measurements are wrong, why they are wrong and include photos. If possible, please mark up a printed version of the map of your parcel and attach photos to show the area that is incorrect. Ex: The shed in the back corner closest to my neighbor at 1100 has been demolished.

Please be patient with the appeals process. If you have a general question or an issue, please email us, or call 309-494-8800.

View and download the Appeals Form (PDF).