Shelby County, TN Environmental Rules: Flood Zones (2026)
FEMA flood zone rules in Shelby County, TN, also called floodplain regulations or special flood hazard area (SFHA) rules, determine flood insurance requirements and elevation standards for new construction.
Key Facts
- Floodplain building
- Permitted, subject to no-adverse-impact showing
- Impact test
- USACOE/FEMA model with upstream development criteria
- Plans
- Must be stamped by TN-licensed professional engineer
- Sinkhole rule
- No increased runoff to sinkholes/dry/drainage wells
- Design standard
- Memphis & Shelby County Drainage Design Manual
Summary
Shelby County allows development in the floodplain, but the County Engineer can require the developer to prove no adverse impact on upstream or downstream facilities, uses, residences or structures before approving it. All stormwater infrastructure standards apply countywide in unincorporated areas.
(6) Development shall be permitted in the floodplain; however, the developer may be required by the manager to demonstrate no adverse impact on upstream or downstream facilities, uses, residences, or related structures. For example, this may be shown by modification of the USACOE/FEMA model by applying full upstream development criteria and new cross sections reflecting the development and depiction of the elevations of all structures, facilities, etc., within the impacted upstream or downstream floodplain.
Full Breakdown
Shelby County Code Sec. 36-108 sets the county's general policy statements for stormwater management infrastructure, and item (6) speaks directly to floodplain development: development is permitted in the floodplain, but the manager (the County Engineer's office) may require the developer to demonstrate no adverse impact on upstream or downstream facilities, uses, residences, or related structures. The code gives a concrete example of how that showing can be made: modification of the USACOE/FEMA hydraulic model using full upstream development criteria and new cross sections that depict the elevations of all structures and facilities within the impacted upstream or downstream floodplain.
This sits inside a broader set of policy statements: all development in unincorporated Shelby County is subject to Article V, construction plans affecting stormwater infrastructure must be stamped by a professional engineer licensed in Tennessee, and a certified record plan must be filed with the manager once a stormwater facility is built. Sec. 36-108(7) separately bars grading or draining a site in a way that increases surface runoff into sinkholes, dry wells or drainage wells, which matters in Shelby County's karst areas near floodplain fringes.
Minimum design, construction, operation and maintenance standards trace to the Memphis and Shelby County Drainage Design Manual (MSCDDM), adopted by resolution of the Board of County Commissioners; until that manual is adopted, the City of Memphis Drainage Design Manual in effect on the ordinance's effective date governs. The article derives from Code 1992 Sec. 30-45 and Ord. No. 292 Sec. 30-125, adopted December 6, 2004.
Violations & Fines
Building in the floodplain without satisfying the manager's no-adverse-impact demonstration under Sec. 36-108(6), or grading/draining in violation of Sec. 36-108(7)'s ban on increased runoff to sinkholes and drainage wells, exposes a project to denial or required design changes before the County Engineer signs off on the stormwater facility record plan.
Frequently Asked Questions
Can I build in a floodplain in unincorporated Shelby County?
Who reviews floodplain development plans in Shelby County?
Does Shelby County restrict drainage into sinkholes near floodplains?
Sources & Official References
Other rules in Shelby County
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