The data layer "Best Available Flood Hazard Area" ("Best Available") is the Effective with additional studies that have been reviewed and approved by the Division of Water. While this data has not yet been submitted to FEMA for inclusion in the FIRMs or NFHL (DFIRMs), this data can be used for general planning, construction, and development purposes. However, Best Available cannot be used for flood insurance determinations. The majority of local jurisdictions have options for using best available data; however typically only the FEMA floodplain limits have been adopted into the local floodplain ordinance.

The floodplain data shown in the Best Available layer is generally more recent than the official FEMA NHFL data in the Effective layer. However, while the Best Available layer has been approved by the Division of Water, this data not gone through the due process standards FEMA requires for publication in the NFHL.

Where a floodway analysis has been completed, an "Approximate Floodway" is included in the Best Available layer. These floodways are based on non-detailed floodplain modeling (i. e. no bridges), but otherwise meet the guidelines for development of floodways in Indiana. These floodways are acceptable for general use in determining jurisdiction for the Indiana Flood Control Act, but should be used with caution. These floodways do not meet the requirements for publication in the FIRMs or NFHL.