Find the main shutoff. Make sure it turns. Tell every adult in the house. If a pipe lets go during a winter blackout, electricity will not be what ruins the floor — water will, and it will keep coming until someone stops it.

The main is the valve for the house, not the small one under a single sink. It is usually where the service comes in. If you have never turned it, you do not know whether it moves, whether it wants a tool you do not own, or whether the direction that feels obvious is the open direction. Those are facts for a quiet afternoon.

A winter blackout takes the heat and leaves the plumbing. A supply line, a washing-machine hose, a pipe on an outside wall can let go after the rooms go cold. The water does not stop because the lights did. Stopping it is a hand on the valve you showed people while the power was still on.

Which way is shut should be readable in the dark. A tag, a mark the household agrees on, anything that does not require a debate with a stiff handle. The middle of water on the floor is a bad time to experiment.

The gas shutoff is a different tool, for a smell of gas or an official order, not for curiosity. If you do not know the difference, a plumber or the utility will show you for free on a quiet day.

Gas you have shut off is not a household experiment to restore. Appliances have their own lighting procedures, and "just turn it back on" can fill the house with a worse problem than the one that made you reach for the wrench. The quiet-day lesson is which valve it is, and that you do not practice on it.

Label the valves. Labels are a technology that survives pulses. They also survive the absence of the one adult who knew. If that adult is at work when the hose fails, the label is the plan you actually have.