What immediate steps should I take within 24 hours after discovering major indoor water damage?

Short answer

Within 24 hours, prioritize safety and stop the water. Shut off the main water supply, cut power to affected circuits if water reached outlets/appliances, and assess whether the water is clean or contaminated. Document everything for insurance, then extract standing water, protect belongings, start aggressive drying with air movers and dehumidifiers, and open up wet building materials where needed. If sewage, large areas, or ceilings are involved, call a mitigation pro immediately.

What to do step-by-step (first 24 hours)

0. Safety first

• Electricity: Before entering wet areas, turn off power to the affected circuits at the breaker. If the panel is inaccessible or you suspect water inside walls/ceiling fixtures, call an electrician or your utility. Do not step into water with live power.
• Water source: Shut off the fixture supply or the main water valve. If the source is from a roof leak, place buckets/tarps and arrange temporary cover.
• Contamination check: If water is from sewage, a drain back-up, or floodwater from outdoors (Category 3), evacuate that area, use PPE (gloves, boots, respirator), and call a restoration company.
• Structural hazards: Stay clear of sagging ceilings or bowed walls. If you see bulges, do not stand underneath. For trapped water in ceilings, place a bucket and carefully poke a small drain hole with a screwdriver only after power is confirmed off.

1. Document for insurance (15–30 minutes)

• Take wide and close-up photos/videos of all rooms, walls, ceilings, floors, and contents, including the water source.
• Photograph standing water depth, damaged finishes, and serial numbers on appliances.
• Keep damaged materials and save receipts for rentals, supplies, and labor.

2. Stop more damage (30–60 minutes)

• Move furniture, rugs, and electronics out of wet areas. Use aluminum foil or furniture blocks under legs.
• Pull back drapes/curtains and remove wall hangings from damp walls.
• If water is still dripping, place pans/towels and protect flooring with plastic sheeting.

3. Extract standing water (1–3 hours)

• Use a submersible pump with a discharge hose for deep pooling, then a wet/dry shop vac for the remainder.
• Squeegees and mops help on hard floors; wring into buckets and dispose into drains that aren’t backed up.
• Lift and roll back carpets; remove and discard the carpet pad if it’s soaked—it usually cannot be salvaged.

4. Open up wet materials (2–6 hours)

• Pop off baseboards/trim with a pry bar and label for reinstallation.
• Drill small “weep holes” at the lowest point of drywall to release water.
• If water wicked up walls, make a flood cut:
  • Cut drywall 12–24 inches above the visible water line or to the next stud bay height.
  • Remove wet insulation; it won’t dry in place.
• Pull toe-kicks off cabinets to enhance airflow underneath. If cabinet boxes are swollen/particleboard, plan for replacement.

5. Start aggressive drying and dehumidification (within hours 2–24)

• Place air movers to blow across wet surfaces and into wall cavities; aim for continuous airflow.
• Run refrigerant or desiccant dehumidifiers in the space.
• Close windows unless the outside air is drier than inside (use a hygrometer). Avoid spreading contaminated air via central HVAC if the water was dirty.

Target conditions
- Indoor RH: < 50% as fast as possible
- Temp: 68–75°F to aid evaporation without baking materials
- Air movers: ~1 per 50–70 sq ft or every 10–16 linear ft of wall
- Dehumidifier: 50–70 pints/day unit per 600–1,000 sq ft (adjust by severity)

6. Clean and disinfect

• For Category 1 (clean) water: wash hard surfaces with a mild detergent, then dry.
• For Category 2/3: use an EPA-registered disinfectant rated for this use. Do not mix chemicals. Porous items deeply soaked (pads, some insulation, particleboard) should be discarded.

7. Monitor

• Check moisture with a pin or pinless moisture meter compared to an unaffected area. Continue drying until readings normalize.
• Expect visible drying over 24–72 hours; mold can begin within 24–48 hours, so keep airflow and dehumidification constant.

Tools and materials

• PPE: nitrile gloves, safety glasses, N95/P100 respirator, rubber boots
• Water control: submersible pump + hose, wet/dry shop vac (12–16 gal), mops, squeegees, buckets
• Drying: air movers/fans, dehumidifier (50–70 pint/day), hygrometer, moisture meter
• Demo/repair: utility knife, pry bar, hammer, oscillating tool, drill/driver, drywall saw, contractor bags
• Protection: plastic sheeting, painter’s tape, furniture blocks/foil, tarps
• Cleaners: mild detergent, EPA-registered disinfectant, rags

Approximate rentals per day: air mover $25–35; dehumidifier $40–70; pump $30–50; shop vac $20–30.

Tips for best results

• Create a temporary drying chamber with plastic sheeting to concentrate dehumidification.
• Lift carpet to “float” it with air movers; replace the pad.
• For photos, artwork, and books: gently separate and lay flat with airflow; freeze waterlogged documents to buy time before specialized restoration.
• Remove outlet/switch covers on affected walls (with power off) to enhance cavity drying.
• Keep pets and kids out of the work area.

Common mistakes to avoid

• Waiting to extract water—every hour increases damage and mold risk.
• Running fans without dehumidifiers, which can just move moisture around.
• Leaving wet insulation and pads in place.
• Opening windows on a humid day that slows drying.
• Bleach on porous building materials—it doesn’t penetrate well and can cause corrosion.
• Tossing everything before adjuster review—keep samples of flooring and finishes.

When to call a professional

• Suspected sewage/contaminated water or musty odors already present.
• Area larger than ~100 sq ft, multiple rooms, or multiple stories.
• Ceiling sagging, structural movement, or water in electrical components.
• Older homes (pre-1980) where cutting into walls may disturb asbestos or lead.
• If you lack the equipment to achieve RH < 50% within the first day.

Typical professional mitigation ranges widely ($1,500–$5,000+), but rapid response often saves flooring and cabinetry, reducing rebuild costs.

Address the source (failed supply line, roof flashing, clogged condensate drain) once stabilized to prevent a repeat. Keep drying gear running continuously and monitor moisture daily until materials reach normal levels comparable to unaffected areas (wood ~12–15% MC).