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Floodplain Permit Practical

You Need a Permit to Build Near a Floodplain in Unincorporated Areas

Williamson County Home & Property

If your land is in or next to a 100-year floodplain, you need a Floodplain Development Permit from Williamson County before you build, add fill, or place a structure. Even if you are outside the floodplain, you may still need a Certificate of Compliance from the county to prove it.

Contact the County Engineer's Office at 512-943-3330. Older floodplain maps for some parts of the county have not been updated in roughly 30 years, so the true flood risk may differ from what the current map shows.

Content last revised 2026-07-11

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