The water is already inside

A flood on the road is a danger you can see coming and turn away from. A flood inside your home is different: it arrives through the door, under the floorboards, up through the drains, and the rooms you live in become the hazard. The rules for water inside the house are about electricity, contamination, and what the water leaves behind.

The Red Cross, Ready.gov and the CDC agree on the order of things: protect people first, then the house. Get out if you are told to, stay out of the water, never touch wet electrics, and start cleaning only when the authorities say it is safe to go back in.

Home flooding safety: get up, get out

If water is coming into your home, move to the highest level you can reach safely — upstairs or the top floor. Do not climb into a closed attic: Ready.gov warns you can be trapped there by rising water with no way out.

If the authorities tell you to evacuate, go at once. Do not wait to see how high the water gets, and do not drive around barricades — responders place them to keep you off roads that are no longer safe. If your household has a family emergency communication plan, use it now: it says who calls whom and where you meet.

Never walk, swim or drive through floodwater — indoors or out. The Red Cross figure is worth memorising: just 6 inches of fast-moving water can knock you over, and 12 inches can carry a vehicle away. Inside a house, the same water hides broken glass, sharp debris and open drains and, worst of all, electricity: downed power lines can charge floodwater, and you cannot see it.

Power, gas and water: only if it is safe

Electricity and floodwater together are lethal. Do not touch electrical equipment if it is wet, or if you are standing in water. If you can reach the main breaker without stepping in water and the authorities have told you to, turn the power off. The CDC advises turning off gas, power and water when there is standing water, fallen power lines, or before evacuating. If reaching the breaker means stepping into water, leave it to the utility or a qualified professional.

The same caution applies to gas. Turn off the gas at the main valve only if you can do so safely and have been told to. Do not use any flooded gas or electrical appliance until a professional has checked it. And never run a generator or any petrol-powered equipment inside the home, basement or garage, or near an open window: carbon monoxide cannot be seen or smelled, and it can kill fast.

What the water carries

Floodwater is not rainwater. The CDC warns it can contain dangerous bacteria from overflowing sewage, plus agricultural and industrial waste. Skin contact alone is not usually a serious risk — but eating or drinking anything contaminated can cause disease. Keep pets out of it too: our pet emergency go-bag guide explains why animals must not drink floodwater or stand in it until officials say the supply is safe.

Do not drink tap water until officials say the supply is safe. The Red Cross advises boiling tap water until sources are declared safe; bottled water is safer until then. Do not use floodwater to drink, wash dishes, brush teeth, prepare food, make ice or make baby formula. Wash your hands with soap and clean water after any contact with floodwater.

Throw away any food that touched floodwater. No amount of washing makes it safe again. The same goes for anything a baby puts in its mouth, and for medicines that were soaked. When in doubt, throw it out.

Going back in: only when officials say so

Return home only when authorities say it is safe — Ready.gov's first rule after a flood. The dangers do not drain away with the water: a house can be structurally damaged, its wiring live, and gas leaking, all invisibly. Enter carefully, watch for slippery floors, and check for damage before switching anything on. For what to keep ready at home, see our emergency kit checklist.

Do not turn the power back on yourself if the house was flooded — have it checked by a qualified professional first. Snakes and other animals may also have come inside with the water.

Before cleaning, photograph the damage for your insurance claim. Standard homeowners insurance does not cover flooding, the Red Cross notes — flood cover is separate.

Cleaning up: dry fast, throw away, protect yourself

Once it is safe to work, speed matters. The Red Cross and the CDC give the same target: clean up and dry your home and everything in it within 24 to 48 hours if possible. After that, mould growth is assumed. Open doors and windows, use fans to blow air outdoors, and run a dehumidifier if you have one. Our winter ventilation guide explains how to keep air moving while a home dries.

Wear protection for the whole job: heavy work gloves, protective clothing and boots, goggles and an N-95 respirator for mould or debris. Ready.gov adds two rules that are easy to forget: people with asthma, lung conditions or weakened immune systems should not enter a building with visible or smelled mould, and children should not take part in disaster cleanup at all. If someone is hurt during the work, our sprains, strains and fractures first-aid guide covers what to do until help arrives.

Throw away anything soft that you cannot clean or dry quickly: mattresses, carpeting, rugs, upholstered furniture, pillows, baby toys and paper products. Remove and discard drywall and insulation contaminated with sewage or floodwater. These things hold contamination in a way no cleaning can fix.

Clean hard surfaces — floors, concrete, wood and metal furniture, countertops, appliances, sinks — with hot water and laundry or dish detergent, then dry them right away. For mould on hard surfaces, the CDC recipe is 1 cup of household bleach per gallon of water, used in a ventilated space with goggles, an N-95 respirator and gloves. Never mix bleach with ammonia or any other cleaner — the fumes are toxic.

What our records show, and what they miss

Our flood records track water as it arrives — warnings, river levels, streets under water — and today's incidents show how often it happens. What they miss is the slower half: the days a family spends drying a home, the food thrown away, the wiring checked room by room. A record logs the flood's depth, not whether the tap water was safe a week later. That is why this guide leans on official safety guidance, and why our methodology page explains what we verify and what we do not.

The short version

  • Never walk, swim or drive through floodwater — 6 inches can knock you over, 12 inches can carry a vehicle away; move to the highest safe level, never a closed attic, and evacuate at once if told to.
  • Turn off gas, power and water only if safe to reach or authorities instruct it — never step in water to reach the breaker, and never touch wet electrics.
  • Do not drink tap water until officials declare it safe; boil it or use bottled water, and throw away food that touched floodwater.
  • Return home only when authorities say so; photograph damage first, and have flooded electrics checked by a professional.
  • Dry your home within 24 to 48 hours; throw away soft items that can't be cleaned and dried; clean hard surfaces with hot water and detergent, mould with 1 cup of bleach per gallon of water, ventilated, never mixed with ammonia; wear gloves, boots and an N-95 mask — and keep children out.