Is It Safe to Turn the Electricity Back On After a Flood?

No. Do not turn the electricity back on after a flood until a qualified electrician has checked your home's wiring, sockets and appliances. That is the consistent instruction from official UK flood guidance, from Scotland to Wales to Northern Ireland: wait for an electrician's approval before turning power back on¹, and do not switch your electricity back on until a qualified person checks it².

The reason is simple. Floodwater can reach wiring, sockets and appliances you cannot see, and the moment the supply returns is the moment a hidden fault becomes a shock or a fire. Official guidance warns that there is a risk of electrocution from appliances that have been in contact with floodwater³, and that it is unlikely anything the water has touched can be used again without a thorough check⁴.

This page sets out what to do now if your supply is still live, where the dangers are, what happens to appliances that got wet, and who is qualified to check your electrics before anything is switched back on. If you are still at the stage of returning to your home, start with After a Flood: Returning Home Safely.

Not until a qualified electrician has checked it

Every official source on this subject says the same thing in slightly different words, and the differences matter less than the agreement. Oxford City Council says to wait for an electrician's approval before turning power back on, and not to use electrical equipment exposed to flood water until it has been checked by a qualified electrician¹. The Scottish Government's ready.scot guidance says not to switch your electricity back on until a qualified person checks it². Lancashire County Council says to get a qualified electrician to check your house before you turn your electricity back on⁹. Belfast City Council says not to use your electricity mains until it has been checked by a qualified electrician⁷.

The check covers more than the fuse box. If any electrical wiring has come into contact with flood water, a qualified electrician will need to check the safety of the system, and the safety of appliances¹⁰. Runnymede Borough Council advises using a registered electrician to assess the condition and damage to electrical wiring, equipment and appliances that have been affected by the flood⁵. Herefordshire Council adds that gas and electricity supplies should remain switched off until a qualified professional has checked the systems thoroughly¹¹.

There is no shortcut here, and no appliance that is worth the risk. Guidance from Public Health Wales is blunt about why: do not switch on electrical appliances that have been in contact with floodwater until a qualified electrician has checked them, as there is a risk of electrocution³. The same warning appears in Scottish Borders Council's flooding advice¹² and in Nottinghamshire County Council's frequently asked questions⁶.

A useful way to think about it is that the flood has moved the danger. Before the water arrived, the risk was water getting into the electrics. Afterwards, the risk is the electrics coming back to life while the house is still damp, with salt, silt and debris inside sockets and appliances. That is why the check has to happen before the supply is restored, not after.

Getting the supply switched off safely if it is still on

If floodwater has entered your property and the electricity is still on, switch it off at the mains, if it is safe to do so⁵. The same instruction appears in West Yorkshire Prepared's flooding guidance, which says to turn off gas, electricity and water only if safe to do so¹³, and in London Assembly guidance for flash flooding, which says to turn off electricity, gas and water if safe to do so¹⁴.

The words "if it is safe to do so" carry the whole weight of this section. North Yorkshire Fire and Rescue Service puts it plainly: isolate electrics only if it is safe to do so, but if in any doubt, call the fire and rescue service on 999¹⁵. Cornwall Council's fire and rescue guidance says never to attempt to turn off the electricity supply while standing in water¹⁶.

If you are evacuating and have time, unplug appliances to prevent electrical shock when the power comes back on, and turn off gas, power and water before you leave¹⁷. That single action protects the house while it is empty and protects whoever comes back to it.

If the supply is already off, leave it off. Do not turn on electricity, gas or water without getting professional advice¹⁸. Do not switch on any utilities until you have checked with an expert that it is safe to do so⁸.

For the wider sequence of switching off utilities before water arrives, see Turning Off Gas, Electricity and Water Before a Flood.

Where electricity is dangerous after a flood

The obvious danger is the socket at waist height. The less obvious ones are the ones that catch people out.

• Standing water. Do not touch sources of electricity while standing in floodwater⁶. This includes extension leads, chargers, lamps and anything plugged in at floor level.
• Downed power lines. Electric currents can pass along downed power lines in flood waters¹³. Keep well away from any cable in or near water and report it.
• Wet appliances. It is unlikely anything the water has touched can be used again without a thorough check⁴. That includes kettles, washing machines, fridges, freezers, chargers and power tools.
• Damp fabric of the building. Wiring inside walls and under floors stays wet long after the surface looks dry, which is why the electrician's check comes before the supply, not after.
• Your own protective kit. Floodwater can be hazardous, so wear rubber boots and gloves in and around the affected property¹⁹. That is protection against contamination as well as against shock.

The practical upshot is that a house can look dry and still be unsafe. Plaster, insulation and timber hold moisture, and an electrician checking the system is looking for exactly that. Do not let a dry surface persuade you to switch anything on early.

Appliances and devices that got wet

The rule for appliances is the same as the rule for the supply, and it is repeated across official guidance in every nation. Do not switch on electrical appliances that have been in contact with flood water unless a competent electrician has cleaned and checked them⁶. Get any electrical appliances that have come into contact with floodwater checked by a qualified electrician before using them again²⁰. Do not use mains powered electrical appliances in areas affected by flooding until advised by a registered electrician that it is safe to do so⁵.

If an appliance has been wet, the sequence is: turn off the electricity at the fuse box, allow the appliance to dry out, and have a qualified professional check it before turning it on²¹. Make sure all affected appliances have been fully tested before using them again, and get specialist advice from electricians⁸.

Two further points are worth keeping in mind. First, "it looks dry" is not a test. Second, an appliance that powers on is not proof it is safe; the check is about insulation and internal damage, which you cannot see. For a closer look at individual appliances, see Using Electrical Appliances After Water Damage.

If the power is still on or came back on by itself

Sometimes the supply was never cut. Sometimes the network restores it while the house is still wet. Either way, the same rule applies: do not use your electricity mains until it has been checked by a qualified electrician⁷.

If the power returns and you are in the property, do not start using sockets or appliances. Turn off the electricity at the mains if it is safe to do so⁵, and if in any doubt, call the fire and rescue service on 999¹⁵. Unplug appliances so they cannot shock you when the power comes back on¹⁷.

A network power cut is not the same as a safety check. The network may have isolated the street, but the wiring and appliances inside your home may still have been wet. Do not switch on any utilities until you have checked with an expert that it is safe to do so⁸, and contact your electricity company about restoring the supply²². For electricity enquiries, call 105⁸.

If your home or business has been flooded, it may also need a safety inspection by the utility companies before you can turn the water, gas and electricity back on²³. That inspection is separate from the electrician's check of your own wiring, and both may be needed.

Who can check your electrics: electrician, gas engineer or supplier

Different parts of the system need different people, and it helps to know which is which before you start ringing round.

The general principle from gov.uk is to get your utilities company or a qualified engineer to check they are safe before turning them back on²⁵. Your personal flood plan should note that you may need gas or electricity engineers to check your supply before turning it back on²⁶. Croydon Council's evacuation checklist advises getting the electrics, central heating and water checked by qualified engineers and any other power suppliers before switching back on²⁷.

On gas specifically, do not turn on gas or gas appliances until your system has been checked by a Gas Safe registered engineer⁷. Turn off the gas supply to appliances that have been flooded or where vents and flues may have been affected, and contact your utility company if in any doubt²⁸. Be wary of damage to gas appliances long after flooding, including central heating systems, radiators and hot water systems⁵.

If you are not sure who to call, start with your supplier, then your insurer, then your council. For electricity enquiries, the national number is 105⁸. For the wider recovery picture, including insurance and support, see After a Flood: Returning Home Safely and Recovery Grants and Help If You Are Not Insured.