Alpharetta, GA Environmental Rules: Flood Zones (2026)
FEMA flood zone rules in Alpharetta, GA, also called floodplain regulations or special flood hazard area (SFHA) rules, determine flood insurance requirements and elevation standards for new construction.
Key Facts
- No-rise threshold
- 0.01 foot maximum increase in flood elevation
- Floodway encroachment
- Prohibited except bridges, culverts, roadways, utilities
- Flood map basis
- FIS for Fulton County dated June 19, 2020
- Administering departments
- Community Development and Public Works Directors
- Maximum penalty
- $1,000/day or up to 60 days imprisonment
Summary
Alpharetta bars any development in a Special Flood Hazard or Future-Conditions Flood Hazard area that would raise the base flood elevation, reduce flood storage capacity, or increase erosive velocities. The Unified Development Code's floodplain management standards apply citywide and are jointly enforced by Community Development and Public Works.
C.General Standards.1.No development shall be allowed within any Area of Special Flood Hazard or Area of Future-conditions Flood Hazard that could result in any of the following:a.Raising the base flood elevation or future-conditions flood elevation equal to or more than 0.01 foot;b.Reducing the base flood or future-conditions flood storage capacity;c.Changing the flow characteristics as to the depth and velocity of the waters of the base flood or future-conditions flood as they pass both the upstream and the downstream boundaries of the development area; or,d.Creating hazardous or erosion-producing velocities, or resulting in excessive sedimentation.
Full Breakdown
Section 3.4.4.C sets the general standards for any project touching an Area of Special Flood Hazard or Area of Future-conditions Flood Hazard: development cannot raise the base or future-conditions flood elevation by 0.01 foot or more, cannot reduce flood storage capacity, cannot change the depth or velocity of floodwaters passing the site's upstream or downstream boundaries, and cannot create hazardous or erosion-producing velocities or excessive sedimentation. Where limited encroachment is allowed under Section 3.4.4.C.2, the applicant must compensate for lost storage within the same ownership boundary, stabilize cut areas to no steeper than a 2 percent slope, and verify no-rise conditions through a step-backwater analysis.
Floodways receive stricter treatment under Section 3.4.4.E: encroachments including fill, new construction, and substantial improvements are prohibited outright, except bridges, culverts, roadways, and utilities that are shown through engineering analysis to cause no increase in base flood elevations. The basis for mapping these areas is the June 19, 2020 Flood Insurance Study for Fulton County, adopted by reference under Section 3.4.1.E. The Directors of Community Development and Public Works jointly administer the ordinance, review permit applications, and interpret disputed floodplain boundaries, with appeals running to the Board of Zoning Appeals and then to Fulton Superior Court.
Violations & Fines
Section 3.4.7 authorizes a written notice of violation, a stop-work order, withholding of the certificate of occupancy, or permit suspension for any floodplain violation. Civil penalties can reach $1,000 per day the violation remains unremedied, and intentional or flagrant violations can bring a criminal citation with a fine of up to $1,000 or imprisonment for up to 60 days, with each day of noncompliance a separate offense.
Frequently Asked Questions
Can I build in Alpharetta's floodplain at all?
Is any work allowed in an Alpharetta floodway?
What map does Alpharetta use to define its flood hazard areas?
Sources & Official References
Other rules in Alpharetta
Compare Alpharetta to another location·View the Georgia environmental rules overview
See something wrong?
Help us keep this page accurate. If you notice an error or outdated information, let us know.
Flood Zones in Nearby Cities
How other cities in Fulton County handle flood zones.