While You Wait for the Truck
Close the main shut-off first. If the house valve is stuck or missing, the curb stop out by the street can cut the supply, but it often needs a curb key. Then go to the breaker panel, but only if you can reach it without standing in water.
Standing water and live outlets are the biggest danger on these calls. If the water has reached outlets, extension cords or electronics, keep out of the room and let the dispatcher know. Move valuables, documents and medications upstairs or onto high shelves.
Dispatcher tip: Tenant with a landlord who is not answering? Close the valve, photograph everything, and send a timestamped text and email so it is clear you moved fast.