Flood Plain Considerations

Similar to many areas in the country, there are areas in the Village of Carol Stream that are within the flood plain. This means that they are in an area of land where there is an increased risk of flooding.  Flood plains are divided into several “Zones” to show various degrees of risk. The predominant “Zones” in the Village are as follows:

Zone   A:  this zone contains areas where the risk is the highest, (once in a 100 years). No Base Flood Elevations determined.

Zone AE:  this zone contains areas where Base Flood Elevations are determined.

Zone   X (Un-dotted): this zone contains areas that are outside the 0.2% annual chance of flooding.

Zone   X (Dotted): this zone contains areas that are within 0.2% annual chance of flooding as well as areas of 1% annual chance of flood with average depths of less than 1 ft. or with drainage areas less than 1 square mile.

In order to determine which one of these zones a parcel of land or a residence is located in, Flood Insurance Rate Maps are used that are developed by FEMA, (the Federal Emergency Management Agency) in 2004 showing the flood plain areas within the Village of Carol Stream.

In order to reduce the insurance costs of flooding as well as for the safety of the people who live within the flood plain or very close to it, there are restrictions placed on building or adding to existing buildings within the high risk areas of the flood plain. The underlying reason for this is that in case of a flood, there would be less property to be damaged and also there would be less buildings to displace the volume which the flood water would occupy, since more buildings would mean flood waters would rise to higher levels and damage even greater number of homes and structures.

 It is however possible to build within the flood plain, but the regulations surrounding this issue can make the matter difficult, costly or sometimes physically impossible.  For example: current regulations require the creation of compensatory storage by the removal of 1.5 times the volume of soil from an area in the back yard (within the flood plain) where a building addition occupies one volume of flood plain below the Base Flood Elevation (BFE).  This would make it difficult for a small back yard that backs into Klein Creek for example to lose that much soil because they added a room addition or a swimming pool.

In addition to the flood plain issues, there are Floodway maps that make it illegal to build or install any structure in certain areas of land.

The FIRM (maps) governing the Village of Carol Stream has the following “Community-Panel Numbers effective date 12/16/2004" These can be viewed through the following links.

17043C0106H

17043C0109H

17043C0204H

17043C0207H

17043C0208H

17043C0501H

17043C0502H

In order to determine if your property is in the flood plain, you can contact the Village of Carol Stream Engineering Department at (630) 871-6220. Also, copies of these maps are available for viewing at the Engineering Department.

A negative determination made by using a FIRM can be challenged. A resident can apply for a review by FEMA by submitting all the evidence including a topographic survey of the lot and the appropriate forms required. 

After reviewing the documents FEMA will issue a “Letter of Determination” indicating their final opinion on that particular lot. This type of challenge usually can be made in cases where the location of the lot, the house or structure on it cannot be precisely determined due to proximity to a less flood risk area on the flood plain map. A resident who intends to challenge the FIRM with regard to his or her property and initiate a review process should contact the FEMA Regional Office in Chicago at (312) 408-5500.

 Please ask for: “a checklist package for submittal to request a letter of determination” to receive the correct forms for this purpose. These forms can also be downloaded and printed through the following link: 

Elevation Certificate