Although walls and ceilings may look dry after a flood, water (in most cases) has entered behind the walls.
Using a moisture meter will determine if you have moisture behind the walls. If you have moisture behind the walls, there is almost a guarantee that you will have mold in the future (often within 36 to 72 hours). Unknown wet insulation is also a great place for odors and mold growth.
Please don’t forget that water damages computers as well. Office equipment, paper files, furniture, art work, and musical instruments all might look dry on the outside but might contain unwanted moisture creating future permanent damage.