Water Damage in Your Home? What to Do in the First 24 Hours

If you are working out what to do after water damage in house, start with two things: make sure nobody is near water and electricity at the same time, then stop the water at its source. Everything else (photos, insurance, drying) comes after those two steps, and most of it can wait an hour without making the damage worse.

Below, the first 24 hours are laid out in order, with source-specific advice for ceilings, washing machines, toilets and dishwashers.

What to do after water damage in your house: the short version

These steps are in the order that keeps people safe and limits damage.

1. Stay out of standing water near electricity. Don’t step into a wet basement or room if water could be touching outlets, power bars, a baseboard heater or the furnace.
2. Stop the water. Close the fixture valve (behind the toilet, under the sink, behind the washer) or the main water shut-off.
3. Photograph everything before you move it. Wide shots of each room, then close-ups of the water line, flooring and damaged items.
4. Call your insurer to report the loss, and write down the claim number and who you spoke to.
5. Remove what water you safely can and move valuables, electronics and paper to a dry room.
6. Start air movement and dehumidification in clean-water losses, and call a restoration company if water got into walls, ceilings, subfloors or insulation.

Electrical safety comes first

Water and electricity are the most serious hazard in a wet home. The Electrical Safety Authority’s flood safety guidance says electricity can move through water or wet flooring and cause a severe shock.

ESA’s guidance is specific. Don’t enter a basement if the water is above electrical outlets, baseboard heaters or the furnace, or if it is near the electrical panel. Instead, call your local electric utility and ask them to disconnect power to the house. In Mississauga that is usually Alectra Utilities; check your hydro bill if you are not sure.

A few rules that follow from that guidance:

• Never touch the panel while standing in water or on a wet floor. If the only route to the panel goes through water, leave it and call the utility.
• Don’t plug in or switch on anything that was wet. ESA says not to use electrical devices that have been in contact with floodwater.
• Have a licensed electrical contractor check the system before power is restored to areas that got wet. ESA’s process has the contractor confirm the system is safe and work with ESA before the utility reconnects. ESA also notes that unlicensed or DIY repairs can delay reconnection and affect insurance claims.

If water is coming through a ceiling near light fixtures, turn off that circuit (or the main, if unsure) at the panel, but only from a dry floor.

Gas appliances need the same caution. If you smell gas (a rotten egg or sulphur smell), Enbridge Gas says to leave right away, leave doors open behind you if you can do it without delay, and call 1-866-763-5427 or 911 once you are outside. Don’t flip switches or use your phone inside.

Stop the water at its source

Once the area is safe, cut off the water. Most indoor leaks come from pressurized supply lines, so closing the right valve stops them within seconds.

If a fixture valve won’t turn or you can’t find it, go straight to the main shut-off. Turn it clockwise until it stops. Then open a tap on the lowest floor to drain the pressure out of the lines.

If water is coming in from outside, such as a storm or a sewer backup through a floor drain, there may be nothing to shut off. Focus on safety and documentation, and report sewer backups to the Region of Peel at 905-791-7800. See why Mississauga basements flood for storm-related flooding.

Hour by hour: the first 24 hours

The times are a guide, not a deadline. Safety always comes before speed.

That last row is the real reason for urgency, per the Health Canada guide to moisture and mould. You don’t need to panic in hour two, but you do want drying underway on day one.

Clean, grey or black water: categories 1, 2 and 3

What the water carried matters as much as how much there is. Restoration companies classify it using the industry standard (IICRC S500), which shapes what you can safely touch and what can be saved.

Categories also get worse over time. Clean water that sits for a day or two in carpet and underpad picks up contamination, and general industry practice then treats it as a higher category.

Health Canada’s guidance is direct about porous materials. Fabrics and soft furnishings that got wet often can’t be properly cleaned and should be discarded. It also recommends a qualified professional when floodwater was contaminated with sewage or chemicals, or when water reached wall or ceiling cavities.

Document everything for your insurance claim

Good records are much harder to recreate later. The Insurance Bureau of Canada’s consumer advice is to document damage when it is safe, be as detailed as possible, and report losses to your insurer or broker.

What to capture:

• Wide photos first. One from the doorway of each room before touching anything, then a slow video walk-through.
• The water line. Close-ups of the highest point water reached on walls, cabinets and furniture.
• The source. The failed hose, cracked pipe, overflowing fixture or ceiling stain. Keep the failed part if you can; adjusters sometimes ask for it.
• Serial and model numbers of damaged appliances and electronics.
• A running log. Who you called, when, claim numbers, and what each person told you.
• Receipts for anything you buy to protect the house, such as fans, a dehumidifier, tarps or a hotel night.

Before you throw anything out, photograph it with something that shows its size and brand. As general practice, keep high-value items until the adjuster has seen them or approved disposal, unless they are a health hazard (sewage-soaked items usually are). If you aren’t sure what your policy covers, our guide to what insurance won’t cover after a basement flood explains common exclusions. This is general information, not legal or insurance advice; your own policy wording decides coverage.

The Insurance Bureau of Canada’s Consumer Information Centre (1-844-227-5422) can answer general questions about how home insurance works if your broker is hard to reach.

What to do by source

Water coming through the ceiling

A ceiling leak means water is pooling above: a bathroom, laundry room, attic or, in a condo, the unit upstairs. Shut off water to the source above, and turn off power to light fixtures in the wet area from a dry floor.

If the drywall is bulging with water, keep people out from under it. It can give way without much warning. Put a bucket and plastic sheeting under it. Some people make a small hole at the lowest point of the bulge to drain it into the bucket, but only do this if the power to that area is off, there are no fixtures nearby and you can stand out of the way. Otherwise leave it for a professional.

In a condo, notify property management right away, and see our guide to water leaking from the condo above. If you rent, tell your landlord in writing the same day.

Washing machine leak or overflow

Most washing machine floods come from a burst supply hose or an overflowing drain. Turn off both taps behind the machine. Unplug it only if the plug and the floor in front of the outlet are dry; otherwise turn off the circuit at the panel.

Washing machine discharge water is usually treated as Category 2 because it carries detergent, soil and whatever was on the clothes, so wear gloves. Once the machine is back in service, check the hoses for bulges or cracks whenever you’re behind it.

Toilet overflow

Lift the tank lid and push the flapper down to stop more water from entering the bowl, then close the shut-off valve behind the toilet. If the bowl is still overflowing, don’t flush again.

What’s in the water matters. A clean tank leak or a supply line failure is Category 1. An overflow from the bowl is at least Category 2, and if it contains feces it is Category 3. In that case avoid skin contact, keep kids and pets out, and remove soaked rugs and bath mats rather than trying to wash them. If an upstairs toilet overflow has come through the ceiling, treat the wet ceiling and anything below it as contaminated too.

Dishwasher leak

Dishwasher leaks often show up as water under the kitchen cabinets or as swelling in laminate or hardwood near the machine. Turn off the breaker for the dishwasher, then close its supply valve under the sink.

The water is grey (Category 2). The bigger problem is water under the dishwasher and cabinets that can sit on the subfloor for days. Pull the kickplate off and look with a flashlight. A wet subfloor needs proper drying, not just a mop.

Other common sources

A leaking hot water tank and a frozen pipe each have their own safety steps. See what to do when your hot water tank is leaking from the bottom, which covers gas versus electric shut-off and rental tanks, and our winter guide on how to prevent and safely thaw frozen pipes.

What doesn’t help (and why)

Using a household vacuum on wet floors. A regular vacuum isn’t built for water and is a shock risk. A wet-dry shop vac is fine for small amounts of clean water, but not for grey or sewage water, which it can spray around the room.

Pointing a household fan at a wet wall and calling it done. Fans dry surfaces. They don’t dry insulation inside a wall, water trapped under laminate or a soaked subfloor. Those need moisture meters to find and specialized drying to fix.

Bleaching everything. Health Canada doesn’t recommend bleach for routine mould cleanup, and bleach does nothing for water trapped inside materials. For sewage-contaminated areas, professional cleaning and removal is the safer path.

Waiting to see if it dries on its own. Small clean spills on hard floors often do. Water in walls, ceilings and under flooring usually doesn’t.

After the first 24 hours

Once the water is stopped and documented, the job becomes drying. For small clean-water losses, our guide to drying water damage yourself explains what works on carpet, hardwood and drywall, and where DIY drying reaches its limit. If drywall is soaked, see whether wet drywall can be dried or should be replaced.

Bring in a professional when water has reached ceilings, wall cavities, insulation or subfloors, when it was grey or black water, or when more than one room is affected. Our emergency water damage restoration service handles extraction, moisture mapping and drying for homes across Mississauga, and you can find other services and areas from our homepage.

If anyone in the house develops breathing problems, or you see mould covering a single patch larger than about 3 square metres, Health Canada recommends a qualified professional assess and clean it. If water ever reached the electrical system, don’t restore power to that area until a licensed electrical contractor has checked it, as ESA advises.