zipradar

Flood zone · South Dakota

Flood zone in South Dakota

Flood zone (FEMA NFHL) data for ZIP codes in South Dakota. Pick a ZIP below to dive into the flood zone summary.

Last verified 2026-05-13 · methodology

What lands here

Pages show the flood zone code, what it means in plain English (1% annual chance zone, 0.2% annual chance zone, or outside mapped hazard), and the base flood elevation where assigned.

Source & refresh

FEMA NFHL. Refreshed quarterly loma updates. Primary source →

South Dakota top concern

Radon Zone 1, agricultural water, tornadoes

South Dakota is uniformly Zone 1 radon. Agricultural runoff drives EPA SDWIS nitrate compliance pressure in small rural systems. Tornado risk peaks April-June.

See South Dakota state page for the full state-level rollup across all 12 dimensions.

Read more on flood zone

Editorial deep-dives explaining the source data, its limits, and how to read it.

3 South Dakota ZIPs