A floodplain is a geographic area subject to flooding; land adjacent to a waterway necessary to contain a flood. Floodplains can be associated with rivers, lakes, streams, channels, even small creeks that are normally dry most of the year. There are two types of floodplains we generally deal with:

   1. 25 year floodplain: an area subject to flooding as a result of the occurrence of a 25 year storm event- a storm that has a 4% chance of occurring in any given year.
   2. 100 year floodplain: an area subject to flooding as a result of the occurrence of a 100 year storm event- a storm that has a 1% chance of occurring in any given year.

See also the Federal Emergency Management Agency (FEMA) Web site for more information on floodplains and floodplain management.

Flood plain regulations are enforced to protect public safety and health. In addition, they encourage sound engineering practices and efficient flood plain management techniques. All construction in Williamson County must adhere to federal flood plain regulations. Regulations are established by the Federal Government and implemented by the  Federal Emergency Management Agency (FEMA). The County Engineer's Office is responsible for examining construction for compliance with local and federal flood plain regulations.

County Engineer's Office are the designated flood plain administrator for Williamson County. Official flood plain maps for the County are available for viewing in our office at 3151 S.E. Inner Loop, Suite B, Georgetown, TX, 78626. Flood plain permitting within various cities in Williamson County are handled by those cities directly.

Currently, residents can come to the County Engineer's Office for consultation to determine whether any specific location is within the flood plain. Alternatively, FEMA maintains a website (http://store.msc.fema.gov) where you can view the same maps we have. A Certificate of Compliance (CoC) is required for all structures in the County Engineer's Office jurisdiction. The Certificate of Compliance permit verifies that no mapped 100 year flood plain exists on the property.

If your property is in the flood plain you will need to elevate the structure higher than the base flood elevation. A flood plain permit will be required. To receive a permit residents must obtain a permit application packet. Included in the packet are instructions and the forms necessary for the flood plain development permit:

    * Flood Plain Development Permit
    * Flood Plain Information Request
    * Flood Plain Development Permit Application Key Elements
    * Elevation Certificate

To complete this process you must hire a surveyor to certify the elevation of the structure and complete the elevation certificate. Completion of the process qualifies the home for the National Flood Insurance Program (NFIP). Development within the flood way is prohibited except with extensive engineering and flood proofing. The Williamson County Flood Damage Prevention Ordinance contains the full text of regulations.

If you have questions please contact the County Engineer's Office at (512) 943-3330.

Important Note: As of November 1, 2005, County Engineer's Office stopped issuing the 3-part form entitled the “Williamson County Flood Plain Management Program Elevation Certificate” and began asking applicants to have their surveyors or engineers use the “Federal Emergency Management Agency (FEMA) National Flood Insurance Program Elevation Certificate” (FEMA Form No. 81-31) relating to new permit applications.

Digital versions and images of flood maps are now available for viewing and printing from the on-line FEMA Flood Map Store at: http://msc.fema.gov/. This on-line store provides paper, scanned images on CD-ROM, and downloads of maps. The Flood Map Store allows users to create a FIRMette at no cost. A FIRMette is a section of the flood hazard map at 100% scale that can be printed on standard paper sizes (8.5 x 11, 8.5 x 14, and 11 x 17).