Electrical safety in a flooded basement

Whether to go down the stairs at all

The Electrical Safety Authority (ESA), mandated by the Government of Ontario to enhance public electrical safety, draws the line at the equipment rather than at a depth. Its flood safety page says not to enter a basement if the water is above the level of the electrical outlets, baseboard heaters or furnace, or is near the electrical panel, and to call the local electric utility immediately and arrange for it to disconnect power to the home. ESA gives the reason in one line: electricity can move through water or wet flooring and cause a severe electrical shock.

In Toronto, the utility's own guide is stricter still. Toronto Hydro's Emergency Ready guide (December 2022) says not to enter a flooded basement unless you are sure the power is disconnected, and to call Toronto Hydro to disconnect it if the basement is flooded and the power is on. The same guide lists staying away from standing water, such as a flooded basement, among its power outage do's and don'ts.

ESA's page about restoring power after storm damage warns that a dark house is not proof of a dead circuit either: power may only be partially interrupted, with a shock hazard present even when the lights and appliances suggest it is off.

Who turns the power off

The instinct in a flooded house is to reach for the breaker. The Government of Canada's flood guidance says not to attempt to shut off electricity if any water is present, because water and live electrical wires can be lethal. If the main power switch was not turned off before the flooding, the Government of Canada says not to re-enter the home until a qualified electrician has determined it is safe to do so.

Toronto Hydro's guide applies the same caution to appliances, saying never to unplug or disconnect an appliance if you have to stand in water to do it, and that this includes damp floors. In ESA's advice and Toronto Hydro's, the safe route runs through the utility.

In the Government of Canada's guidance, shutting off power is a job for before the water arrives. Its preparation list says to learn how to turn off utilities such as electricity and gas, and notes that local authorities may instruct you to shut them off. ESA's flood page adds that if you have to evacuate before flooding, electrical appliances and devices should be moved out of the home or to an area above the expected level of floodwater.

Why ESA says not to let wiring dry out

ESA publishes a guideline for flooding, water ingress or damage, revised May 1, 2025. It opens with the Ontario Electrical Safety Code, quoting Rule 2-032 3): electrical equipment that has been exposed to ingress of water shall be subjected to evaluation to ascertain whether or not it may be placed back into service. ESA's guideline says such equipment and wiring may be dangerous if re-energized without proper evaluation, reconditioning or replacement by qualified persons, and that in many cases the water can carry soil, sewage, oil or chemicals, a contamination that ESA says may lead to fire or shock hazards.

ESA's guideline says that allowing equipment and wiring to dry out and then re-energizing it is not a recommended practice, and that in many cases replacing the affected wiring and equipment is the only safe alternative, even if no visible damage is apparent. The same ESA document says that equipment with electronic components, such as breakers, smoke and carbon monoxide detectors, ground-fault and arc-fault circuit interrupters (GFCIs and AFCIs) and surge protective devices, must be replaced if it has been sprayed or submerged, because there are no methods of ensuring these life safety devices will work as intended after exposure to water.

ESA's guideline also says that submerged panelboards, receptacles, switches, light fixtures and electric heaters need to be replaced or repaired by the original manufacturer or an approved representative, and that components replaced because of water damage should be destroyed rather than re-used in another application. The guideline's own summary of the stakes is short: restoring power after a disaster is a priority, doing it safely is a necessity, and one disaster is enough.

What stays unplugged

ESA, Toronto Hydro and the Government of Canada all treat flooded appliances as dangerous to switch on. ESA's flood page says not to try to use electrical devices that have been in contact with floodwater. Toronto Hydro's guide says not to use flooded appliances, outlets, switches or breaker panels until a qualified electrician has checked and cleaned them. The Government of Canada warns that appliances that may have been flooded pose a risk of shock or fire when turned on.

ESA's guideline is the most specific about who does the checking, saying not to plug in, re-energize or attempt to use electrical appliances that have been submerged or sprayed with significant jets of water until a manufacturer approved service agency has serviced them, and ESA adds that some submerged equipment may have to be replaced while other equipment may be salvageable when serviced by qualified personnel. The same ESA list of submerged equipment that needs replacing or repair by the original manufacturer or an approved representative names boilers, electric motors, and appliances such as water heaters, ovens, ranges and dishwashers.

How the power comes back on

Reconnection is a sequence with ESA in the middle of it. The ESA flood page says not to attempt repairs yourself, and to hire a Licensed Electrical Contractor (LEC) to check the home's electrical system and determine whether it is safe to have the utility restore power. ESA's guideline adds that once power has been disconnected, the utility may require written authorization from ESA before reconnecting it.

In the order ESA's flood page sets out, the contractor files a notification with ESA so there is a record of the work, then notifies ESA when the work is complete, ESA informs the utility that it is safe to reconnect, and the utility reconnects when it is able to do so. ESA says to ask the contractor for a copy of the ESA Certificate of Acceptance for your records and insurance purposes, and warns that hiring an unlicensed contractor or attempting repairs yourself could delay the reconnection, affect insurance claims and create safety hazards.

ESA's flood page also says that if the electrical system was affected, you may have to wait for the utility to restore power, because the utility may have to assess the damage and you may have to arrange repairs. None of the steps in ESA's sequence belongs to a restoration company. They belong to the electrical contractor, to ESA and to the utility.

Hiring the electrician, and what this index can tell you

ESA's page on hiring a Licensed Electrical Contractor gives three checks. ESA says to ask for the contractor's ECRA/ESA licence number, which proves it can operate an electrical contracting business in Ontario, and to verify that number on ESA's Find a Contractor tool. ESA also says to ask for the Certificate of Acceptance once the work is complete, and, when a general contractor brings in the electrician, to make sure that electrician is an LEC and gets an ESA permit. ESA warns that if an insurance claim links to work by an unlicensed electrician, the claim may be denied.

This index cannot run those checks for you. Of its 294 records, Google Maps labels 211 as water damage restoration services and 29 as building restoration services, with 4 plumbers, 4 general contractors and 2 construction companies among the rest, and it labels none of them an electrician. No field in the records holds a licence status, and none of the Google Maps or website text the index stored for these firms mentions an ECRA or ESA licence.

The companies listed under water damage restoration are there for the water, and ESA's rules decide who handles the wiring. Restoration credentials are a separate question, covered in the note on mould removal licensing in Ontario, and the basement flood cleanup cost guide lists published Toronto cleanup prices, each with its source named.

Generators, sump pumps and the cleanup clock

The Government of Canada's flood guidance notes that flooding may cause power outages, and says never to operate a fuel-burning generator inside a home, garage, basement, crawlspace or shed, to operate portable generators at least 6 metres (20 feet) from all homes or buildings, and not to operate generators in flooded areas. Toronto Hydro's guide adds never to connect a generator directly to the home's wiring, and to keep cords and generators safely out of water.

The sump pump is where the outage and the flood meet. The City of Toronto's subsidy page notes that sump pumps can lose power during severe storms and suggests considering a battery back-up. The City's Basement Flooding Protection Subsidy, which offers up to $6,650 per property, covers a battery backup for a sump pump among other work, with the conditions set out in the note on the first six hours after a basement flood.

The cleanup has its own clock. The Government of Canada says to clean up flooded areas as soon as it is safe to do so and, if possible, within 48 hours to avoid mould growth, and Desa Contracting's Toronto guide says mould can start growing within 24 to 48 hours. By Toronto Hydro's rule, safe starts with being sure the power is disconnected, so the call to the utility is also the first step of the cleanup.