Water Damage: What to Do in the First 24 Hours

Updated 2026-08-14

Water keeps moving while you decide what to do. It wicks up drywall, slips under baseboards, and soaks into subfloor within hours, and mold can begin colonizing wet materials in as little as 24 to 72 hours. The order you do things in matters more than how fast you scrub: make it safe, stop the water, document before you clean, protect what you can, then make an honest call on DIY versus professional drying.

Step 1: Make the area safe before you step in

Electricity first

Never walk into standing water in a room where the power is on. If you can reach your breaker panel without touching water, shut off the circuits feeding the affected rooms, or the main breaker if unsure. If the panel itself is in a flooded basement, stay away and ask your utility to cut power at the meter. Unplug nothing while standing in water; wet outlets and submerged plugs can energize the water around them.

Structural and other hazards

• A sagging or bulging ceiling is holding water and can collapse; stay out of the room below it.
• Watch for slick floors, especially stairs and tile.
• If you smell gas, or the water heater’s burner got wet, leave and call the gas company first.
• If sewage is involved, keep children and pets out, and wear gloves, boots, and eye protection if you must enter.

Know what kind of water you are dealing with

The IICRC, the certifying body for the restoration trade, sorts water into three categories. Category 1 is clean water from a supply line or rainwater. Category 2, gray water, comes from sources like a washing machine drain or dishwasher overflow. Category 3, black water, includes sewage backups and river or storm-surge flooding. Category 1 is a candidate for DIY; Categories 2 and 3 generally are not, because contamination, not just moisture, becomes the problem. Our guide to water damage categories explained covers how each changes the cleanup.

Step 2: Stop the source

For anything involving your plumbing, close the main shutoff valve. In most US homes it is where the water line enters the house: a basement or crawl space wall facing the street, a utility room, or near the water heater. In warm climates, check a covered box near the foundation. If the valve is seized or missing, the curb stop at the street can be closed with a meter key, or your water utility can shut it for you.

Faster, more targeted options when you know the source:

• Toilet or sink supply line: close the oval valve on the wall behind the fixture.
• Water heater leak: close the cold inlet valve on top of the tank and shut off its power or gas.
• Washing machine hose: close both valves behind the machine.
• Roof leak: buckets and tarps inside; never climb a wet roof in a storm.
• Sewage backup: stop running water anywhere in the house, since every drain feeds the same line.

Step 3: Document everything before you clean anything

This is the step people skip under stress, and the one that costs real money later. Most homeowners policies give you a duty to mitigate, meaning you must take reasonable steps to prevent further damage, but you also carry the burden of proving what was damaged. Do the proof first. It takes 20 minutes.

• Take wide shots of every affected room, then close-ups of damaged walls, flooring, and belongings.
• Shoot a narrated video walkthrough noting what happened and when.
• Photograph the source: the burst pipe, the failed hose, the stained ceiling.
• Stand a tape measure in any standing water and photograph the depth.
• Capture make, model, and serial numbers of damaged appliances and electronics.
• Throw nothing away yet. Adjusters may want to inspect damaged items; keep a cut sample of any carpet or flooring you remove.
• Save every receipt from this point forward: fans, dehumidifier rental, tarps, even a hotel night. Reasonable mitigation costs are typically reimbursable.

Call your insurer’s claims line the same day, even if you doubt the damage will exceed your deductible. Early notice protects you, and asking questions is not the same as filing. Our walkthrough of the water damage insurance claim process covers what happens after that first call.

The first 24 hours, prioritized

What to move and save

Work top down by value and vulnerability:

• Electronics and anything with a plug go up and out first. Do not power on anything that got wet.
• Documents, photos, and books: seal what you cannot dry immediately in freezer bags and freeze them. Freezing halts deterioration until a document restoration service can treat them.
• Furniture: move it out of wet rooms, or put aluminum foil or wood blocks under the legs so stain does not bleed into wet carpet.
• Area rugs come up immediately. Curtains get looped over their rods, off the wet floor.
• Upholstery cushions stand on edge to drain and dry evenly.

DIY drying or professional help

When DIY is realistic

DIY is realistic when all of these are true: the water is Category 1, you caught it within hours, the wetting is limited to surfaces you can see and reach, and nothing soaked into wall cavities, insulation, or hardwood. A typical DIY setup is a rented dehumidifier (roughly $60 to $125 per day) plus two or three air movers ($25 to $45 per day each), running continuously with interior doors open. Expect several days of runtime, not an afternoon. Surfaces that feel dry can still be wet inside; with a moisture meter, materials count as dry when they match a reading from an unaffected room.

When to call a pro

Call a restoration company the same day if any of these apply:

• The water is Category 2 or 3
• Water reached wall cavities, insulation, ceilings, or under flooring
• Hardwood floors are cupping, or laminate is swelling
• Water stood for more than a few hours, or the loss happened while you were away
• The HVAC system or ductwork got wet
• A finished basement flooded

The reason for urgency is the mold window. Mold can establish on wet drywall, wood, and carpet pad within 24 to 72 hours, and once it does, you are paying for remediation on top of drying. Getting equipment running inside the first 24 to 48 hours is usually the difference. If you are already past that window, read our guide on mold after water damage before disturbing anything.

Professional drying costs vary with the water category and square footage. Get a fast estimate from our water damage cost calculator, and compare typical local pricing with our state-by-state cost data.

What a professional crew actually does on arrival

Knowing the standard sequence helps you spot a competent crew, and a sloppy one:

1. Inspection and mapping. A technician (look for IICRC WRT certification, and ASD for structural drying) uses pin and pinless moisture meters plus a thermal imaging camera to map how far the water traveled, including inside walls, then classifies the loss, which drives the drying plan.
2. Extraction. Truck-mounted or portable extractors pull standing water; weighted wands press water out of carpet and pad. Extraction removes far more water per hour than evaporation, which is why pros extract before they dry.
3. Controlled demolition. Baseboards come off so wall cavities can breathe. Saturated carpet pad is bagged and removed. Soaked drywall gets a flood cut above the waterline rather than whole-wall tear-out.
4. Antimicrobial treatment. Affected surfaces commonly get an antimicrobial application on Category 2 and 3 losses, based on an assessment of the contamination and materials involved rather than as a blanket requirement.
5. Drying setup. Low-grain refrigerant (LGR) dehumidifiers and a calculated number of air movers go in, sometimes with floor-mat systems that pull moisture up through hardwood, plus HEPA air scrubbers on contaminated losses.
6. Daily monitoring. The crew returns each day, logs moisture readings against a dry standard, and repositions equipment. A typical structural dry-down runs three to five days. Daily logs go to your insurer, and most firms write estimates in Xactimate, the same software adjusters use.

FAQ

Should I call my insurance company or a restoration company first?

Do both within the first few hours, but if you must choose, stop the water and get a mitigation crew moving first, then call the insurer the same day. Most policies require you to prevent further damage, and insurers generally do not expect you to wait for an adjuster while your subfloor soaks. Just document thoroughly before anything is removed or discarded.

Can I dry it out with box fans and open windows?

For a small, clean, same-day spill on hard surfaces, that may be enough. For anything that reached drywall, pad, or subfloor, household fans move air but do not remove moisture from it; without a dehumidifier you are mostly redistributing humidity around the house. Rented air movers plus a real dehumidifier, or a professional setup, dry structures in days instead of weeks.

How do I know if water got inside my walls?

Warning signs include baseboards pulling away, paint bubbling, a musty smell, and drywall that feels cool or soft above the visible waterline. The reliable answer comes from a moisture meter or thermal camera, a standard part of any professional inspection. If water stood against a wall for more than an hour or two, assume the cavity is wet until proven dry.

Is it safe to stay in the house?

Usually yes for a contained Category 1 loss once power issues are handled. Leave if sewage is involved, ceilings are sagging, the electrical panel got wet, or anyone in the home has respiratory problems and the loss is more than a day old. If you relocate, keep receipts: additional living expenses (ALE) coverage, which most homeowners policies include, reimburses reasonable costs when a covered loss makes the home uninhabitable.