Williamson County, TN Environmental Rules: Coastal Development (2026)
Key Facts
- Coastal
- N/A (landlocked county)
- Drainageways
- 50% kept open space
- Stream/Wetland Fill
- Corps 404 + ARAP
- River
- Harpeth watershed
Summary
Williamson County is landlocked in Middle Tennessee, so coastal rules do not apply. Development near its streams and drainageways is instead governed by open-space buffers, floodplain limits, and erosion controls protecting the Harpeth River system.
Fifty (50) percent of the drainageway shall be maintained as open space. Drainageways shall be protected in such a way that the entire length can continue to function and be used for drainage purposes.
Full Breakdown
There is no coastline or tidal shoreline here; the relevant protections are river-corridor and drainageway rules. Zoning Ordinance Section 7113 requires half of any drainageway to remain open space and stay functional for drainage. Building near streams also triggers floodplain elevation standards (Section 7111) and mandatory erosion and sedimentation plans (Section 7230). Altering a stream channel, filling wetlands, or streambank work can require a federal Army Corps Section 404 permit plus a TDEC Aquatic Resource Alteration Permit (ARAP). These layered rules protect the undammed Harpeth and its tributaries.
Violations & Fines
Disturbing a protected drainageway or filling a stream without approval brings stop-work orders and restoration. Unpermitted work in state waters can draw TDEC and Army Corps penalties reaching thousands of dollars per day.
Frequently Asked Questions
Are there coastal or shoreline rules here?
Do I need a permit to work in a stream?
Sources & Official References
Other rules in Williamson County
Compare Williamson County to another location·View the Tennessee environmental rules overview
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