Water has reached an outlet or the breaker panel.

Get everyone out of that area and do not attempt to switch anything off. If water has reached the breaker panel, or you would have to stand in water to reach it, the shutdown has to happen upstream at the meter, and that is the utility’s job. Call their emergency line and tell them there is water at the electrical service.

Property is replaceable. This is the one instruction on this site that has no qualifications on it.

In the first minutes

Everyone out of the affected area, and out of the building if the panel is in the only route through it.
Nobody touches anything metal: pipes, radiators, appliances, the panel, metal door frames.
Call the utility. Say there is water at the electrical service or the meter. This is an emergency category for them.
Call the fire service if there is smoke, arcing, buzzing, or if anyone has been shocked.
Stop the water only if you can do it without going near anything electrical. Where the main shut-off is.
Do not use a wet vacuum, a pump, or a fan in the area until the supply is confirmed off.

If someone has been shocked

Do not touch them while they may still be in contact with the source. Call emergency services. Anyone who has taken a shock should be assessed medically even if they seem fine, because electrical injury can cause heart rhythm problems that appear later and internal injury that is not visible.

What happens next

The utility isolates the supply, usually by pulling the meter or disconnecting at the pole.

An electrician assesses the panel and the circuits. Expect this to be conservative, and expect it to cost money, because the honest answer for submerged equipment is usually replacement rather than drying.

The industry position on this is consistent: electrical equipment that has been submerged, including breakers, panels, outlets, switches, and connected appliances, is generally replaced rather than dried and reused. Contacts corrode, insulation degrades, and the failure mode is delayed. A panel that works after being dried out can fail months later.

Reconnection may need an inspection. In many jurisdictions the utility will not restore supply to a flooded service until an electrical inspector has signed it off. That is a queue after a flood, which is one more reason to get the electrician engaged on day one.

What usually has to be replaced

The panel and its breakers, if water reached them.
Outlets, switches, and junction boxes that were submerged.
Any wiring that sat in water, particularly older insulation types.
Appliances that were submerged, especially anything with a motor or a control board.
The furnace or air handler, if it was in the flooded area. Do not run it.

An electrician who tells you it all needs replacing after a submersion is not necessarily overselling. Ask them to explain what was wet and how they know.

Documenting it

Before anything is removed, and from a safe distance:

Photographs of the water level against the panel, an outlet, or a wall, with something for scale.
The waterline marked on the wall in pencil or tape.
Every affected appliance, with model and serial numbers.
The utility’s and the electrician’s written findings.

The height of the water is the single most important fact in the claim, because it determines what was submerged. Documenting a water event properly.

Insurance

Two separate questions, and they often have different answers.

How did the water get there? A burst pipe or an appliance failure is normally covered. Ground water, surface water, or a drain backing up usually is not, without the relevant separate cover. Water that arrives from the ground and backup through a drain both have their own rules.

What did it damage? Electrical equipment damaged by covered water is normally part of that claim.

Report it the same day, and say the words “water has reached the electrical service”, because that changes how quickly it is handled. The wider electrical coverage picture.

The short version

Do not reach for the panel. Get out, call the utility to isolate at the meter, and call emergency services if anyone has been shocked or there is arcing. Submerged electrical equipment gets replaced rather than dried. Photograph the waterline before anything moves, and expect an inspection before the supply comes back.