Water damage is unusual among household disasters because the worst of it is not the event. A burst supply line stops. The damage that costs money accumulates quietly over the following weeks, inside materials, and most of whether that happens is decided in the first two days.
What follows assumes clean water from a supply line or an appliance. Anything involving sewage or floodwater from outside is a different problem with different health implications, and it belongs to specialists from the first minute.
Hour one: stop it and make it safe
Find the main shutoff valve and turn it off. Do this before anything else, and if you do not know where yours is, go find out now rather than at two in the morning in six inches of water.
If water has reached anything electrical, or is anywhere near the panel, kill the power at the main breaker and leave it off until an electrician says otherwise. Water and wiring is the part of this that hurts people rather than budgets.
Hours one to three: photograph everything
Before you move a single item, photograph the room from every corner. Then photograph the damaged items individually, including labels and serial numbers where they exist.
People skip this because they are busy dealing with the water, and then spend weeks arguing about what was there. Your photographs are the only record that exists of the state of things before you started cleaning up, and an adjuster who arrives on day five is looking at a scene you have already changed.
Keep the failed part. The section of pipe, the burst hose, the cracked fitting. It answers the question of cause, and cause decides whether the claim is paid.
Hours three to six: call the insurer before the contractor
Call your homeowners insurer and open a claim, even if you are not certain you will pursue it. Opening a claim costs nothing and closing one is easy; discovering on day ten that your policy required prompt notice is not.
Ask two questions specifically. Whether they want to send their own contractor, and whether emergency mitigation is covered. Most policies require you to prevent further damage and will pay for that work, but will not pay for a full repair you commissioned yourself before they had a chance to inspect.
Day one to two: dry it properly, not quickly
This is where most of the money is lost, and the distinction matters more than it sounds.
Drying quickly means the surface is dry to the touch and the room smells fine. Drying properly means the moisture held inside drywall, subfloor, studs, and insulation has gone. Surfaces reach touch-dry in a day. Structure takes weeks, sometimes longer, and a wall that is dry on the outside and wet inside is where mold begins. The CDC, which tracks the health effects of damp indoor spaces, is blunt about how fast mold follows standing moisture.
Practically: get air moving, keep the heat moderate and steady rather than blasting it, and lift what can be lifted. Carpet and pad should come up. Pad in particular holds water and is cheap to replace relative to the floor beneath it. Pull baseboards if water got behind them.
Blasting heat at a wet wall drives moisture deeper and dries the surface first, sealing the rest in. Dehumidifiers work better than heaters here, and a rental company will rent industrial ones by the week for less than most people assume.
Which items to save and which to let go
Decide this early, because indecision is what ruins the salvageable ones.
Hard goods clean up: dishes, metal, sealed furniture, most electronics that were not powered on when they got wet. Take those out of the room and let them dry somewhere warm rather than leaving them in the damp.
Anything upholstered or padded that sat in water for more than a day is usually finished, and the same goes for particle board furniture, which swells and does not come back. Photograph each item before it goes to the curb, because a claim on contents needs evidence and the sofa will not be available for inspection.
Paper and photographs are the exception worth effort. Freezing wet documents and photographs stops the damage where it is and buys you weeks to deal with them one at a time, which is a trick professional restorers use and almost no homeowner knows.
When to bring in a restoration company
Two conditions, either one of which is enough. The water reached more than one room or went through a floor. Or it sat for longer than a day before anyone found it.
Below that, a household with a couple of rented dehumidifiers and some patience can handle it. Above it, the equipment matters: commercial dehumidifiers pull moisture at a rate rental-counter units do not approach, and the difference shows up as days on the drying clock.
Ask a company three questions before signing anything. Whether they will provide daily moisture logs. Whether they bill the insurer directly. And whether the paperwork you are being handed at the door is a work authorization for emergency mitigation only, or an agreement covering the full repair as well. Those are different documents and people sign the second while believing they signed the first.
What to hold off on
Do not re-drywall. Do not relay flooring. Do not repaint. Every one of these traps moisture and every one will need doing twice.
Get a moisture-meter reading before anything is closed up. A restoration company will provide one; a rental meter costs little. The number, not the calendar and not how it looks, is what says the structure is ready.