Go to the FEMA website and use their mapping tool (Map Viewer) to help you determine whether your project is in Zone A (the 100-year floodplain). See the example of FEMA 100-year floodplain research in the Documentation Toolkit. Use the following steps:

Search by your project address, or state and zip code.
Use the legend to determine whether your project is in Zone A. 
If your project is in Zone A, determine the elevation of the 100-year floodplain and see if your project is at least five feet above this elevation.
If your project is not located in Zone A, your site is in compliance.
If you zoom in to the state or county level first, you will be able to see data that may not be obvious at the address level; projects in areas corresponding to “DFIRM Data Availability” will have the most luck in easily determining their floodplain.