Flood water is never clean
Water that crossed lawns, streets and soil carries sediment, fertilizer, fuel and sewage overflow. Under the IICRC S500 standard it is Category 3. Carpet, pad, insulation and drywall it touched are removed, and hard surfaces are cleaned and treated before drying.
The local flood picture
Zone AE and Zone X are the two most common FEMA designations here, and the low-lying ground the river and Crooked Creek spill onto is mapped in AE and A zones. Flooding is not only a high-risk-zone problem: more than a quarter of flood claims come from outside mapped high-risk areas. In September 2009, 10 to 20 inches of rain fell on metro Atlanta in under 24 hours and more than 20,000 buildings were badly damaged.
After the water goes down
Mud is shoveled and washed out, wet materials are cut out above the flood line and the structure is dried with dehumidifiers and air movers. The National Weather Service record of the 2009 flood shows what big rain does here, and the city's floodplain management page covers flood maps and insurance.



