Prewash fabrics in cool water with powdered laundry detergent. Hot water may set stains. Add an enzyme presoak to help remove protein stains, such as sewage. Wash clothing in small loads with the hottest water safe for the fabric. Use slightly more laundry detergent than normal.
Powdered detergents are more effective in removing clay and ground-in dirt.
If mildew appears on clothes, wash them using chlorine bleach if safe for the fabric, or soak in oxygen bleach and hot water, then wash. Continue to wash as many times as needed. Do not dry fabrics in a dryer until you are satisfied with the results. Dryer heat can set stains, making them impossible to remove. Bacteria from floodwaters can stay alive on fabrics for a long time.