The first hour decides what this costs you.

First move, always: stop more water from arriving. Find the shutoff — the little valve behind the toilet or under the sink for a fixture, the main valve where the line enters the house for anything bigger. If you don't know where your main shutoff is, go find it right now, on a dry calm day, so you're not learning during a flood. Turn it clockwise, righty-tighty, until it stops.

Then, before you go wading in: if the water is anywhere near outlets, cords, or the breaker panel, cut the power to that area at the breaker first. Water and electricity is the one place on this whole list where the deadpan stops. You do not walk into standing water that might be live to save a rug.

Standing water is the part of the clock you can actually beat, so beat it. A wet/dry vacuum pulls up in ten minutes what an hour of towels won't touch, and it gets it out of the low spots and grout lines where the water is happiest. Work from the edges of the room inward so you're not chasing it around, and empty the tank outside or into a drain, not back onto the floor you're trying to save.

This is the single highest-leverage thing you own for a flooded floor, which is exactly why you buy one before the emergency. Renting one at 11pm when the aisle's closed is not a plan. If all you do in the first hour is stop the source and vacuum the standing water, you've already changed the ending.

Water you can see is only half of it. The rest has wicked up into baseboards, under the flooring, into the bottom of the drywall, and it will sit there being a mold farm unless you force it out. Point fans low and across the floor, not down at it — you want air moving over the wet surfaces. Open windows if it's drier outside than in. Run a dehumidifier if you've got one, closed up in the room, and empty it often.

If baseboards or drywall are soaked, pulling the baseboard off and cutting a few inches of soaked drywall isn't overkill — it's the difference between drying the cavity and sealing the damp inside a wall to ferment. Keep the air moving for days, not hours. A moisture meter tells you when a wall that feels dry actually is.

Somewhere in the first hour — ideally before you've hauled the wet rug out — take pictures. A lot of them. Wide shots of the room, close-ups of the damage, a slow video narrating what happened and when. Get the source, the standing water, the soaked furniture, the water line on the wall. Then, and only then, start hauling things out.

If this is going to be an insurance claim, the documentation you take in the first hour is worth more than anything you'll do later, because an adjuster can only pay for damage they can see, and you're about to erase most of the visible evidence by cleaning it up. This is also the moment to check what your policy actually covers — sudden burst pipe, usually yes; flood from outside, usually a separate policy entirely.