Stop the water at its source or at the main shutoff, keep people away from any water near electrical outlets or panels, photograph and video everything before moving items, move contents off wet flooring, then begin water extraction. Wet materials should be extracted and drying equipment running within the first few hours, because absorption into drywall, insulation, and subfloor continues the entire time water sits.
Standing water should be extracted within the first few hours and drying equipment should be running within 24 hours. Mold can begin growing on wet organic materials in about 24 to 48 hours, and beyond roughly 72 hours the likelihood of removing drywall, insulation, carpet pad, and flooring rises sharply. Waiting does not pause the damage; absorption continues every hour water is present.
With professional equipment running continuously, most water-damaged structures dry in three to five days. Drywall and carpet often reach dry standard in two to three days, while hardwood flooring, plaster, dense subfloor layers, and concrete can take a week or more. Drying is finished when moisture meter readings match unaffected reference materials in the same building, not on a fixed schedule.