How to manage electrical hazards before, during, and after a flood — including when to turn off your electricity, what to check before restoring power, and which appliances are safe to use.
Flooding and electricity form a lethal combination. Water entering a building can reach live electrical outlets, submerge appliances, saturate wiring within walls and floors, and interact with downed external power lines to electrify entire areas of floodwater. People drown in floods, but a significant proportion also die from electrocution — from flooded consumer units, from wading through water in contact with a live source, or from attempting to operate electrical equipment in flooded buildings.
Managing this hazard requires decisions made before the water arrives, during active flooding, and through the recovery period.
When a flood warning is issued for your area:
| Action | When | Purpose |
|---|---|---|
| Turn off electricity at the main switch | Before water enters | Prevents live circuits being submerged |
| Move electrical appliances to upper floors | Before water enters | Protects them from water damage and prevents submersion |
| Unplug all appliances | Before water enters | Prevents floating appliances pulling cables into water |
| Note the location of your consumer unit | Any time | Know where to isolate quickly |
| Check if your consumer unit is above flood level | Now | If it may be submerged, you cannot safely restore power yourself |
The main isolation switch is in your consumer unit (fuse box). In a UK home this is typically the large switch at the top of the panel — turning it off isolates all internal circuits from the incoming supply.
⚠️ If water may rise above the level of your consumer unit, turn the electricity off before it reaches that level. Once a consumer unit is submerged or has had water contact, it must not be switched on again until inspected by a qualified electrician. Attempting to restore power to a wet consumer unit is one of the most common causes of post-flood electrocution.
Before entering any flooded area on foot:
You cannot tell if floodwater is electrified by looking at it. It does not spark. It does not glow. It looks like any other floodwater.
Signs that floodwater may be electrified:
If you suspect electrified floodwater: do not enter. Call 999 and report the suspected location. Wait for the network operator to de-energise the area.
If you must evacuate through or from a flooded building:
This is the period when most post-flood electrical incidents occur. Residents eager to restore normality operate appliances or restore power before the electrical system is safe:
| Check | Who Performs It |
|---|---|
| Consumer unit / fuse box inspected for water contact | NICEIC/NAPIT registered electrician |
| All wiring in flooded areas inspected | Registered electrician |
| All submerged sockets and switches inspected | Registered electrician |
| Any appliance that was submerged tested or replaced | Appliance service engineer or replacement |
This is not a check you can do yourself. The risks are:
Do not restore power until a qualified electrician has inspected and issued a written certificate that it is safe to do so.
| Appliance Type | After Submersion |
|---|---|
| White goods (washing machine, dishwasher, fridge) | Do not use; must be inspected by service engineer or replaced |
| Small kitchen appliances (kettle, toaster, microwave) | Do not use; replace — the cost of inspection exceeds replacement |
| Television, audio equipment | Do not use; must be fully dried and tested by service engineer |
| Boiler (gas or oil) | Do not use; must be inspected by Gas Safe engineer (gas) or OFTEC engineer (oil) |
| Smoke and CO detectors | Replace immediately — sensors compromised by water |
| Extension leads and cables submerged | Replace — do not use |
| Phone and laptop chargers submerged | Replace |
The drying-out rule: An appliance may appear to work after drying for several days. Corrosion inside the appliance continues after visible moisture has dried. Using a corroded appliance can cause a fire weeks after the flood event. If in doubt, replace.
While waiting for inspection:
Photograph all electrical damage before any repair or removal. Electrical flood damage is covered under most home insurance policies:
Your insurer may require a written inspection report from a registered electrician before paying out. Get this in writing.
| Situation | Action |
|---|---|
| Flood warning issued | Turn off main switch; unplug; move appliances high |
| Water entering building | Turn off main switch if still safe to reach |
| Consumer unit may be submerged | Turn off before it reaches that level |
| Flooded area — is water safe to enter? | Never assume safe; check for downed lines; no tingling |
| After flood — can I turn power on? | No — electrician inspection first |
| Submerged appliance | Do not use; inspect or replace |
| Smoke/CO detectors after flood | Replace immediately |
| Temporary power during recovery | Battery devices; outdoor generator only |
Take Electrical Safety During and After Flooding with you — no internet needed when it matters most.
downloadGet on Google Play