Flooding in Ontario is typically caused by:

  • rapidly melting snow
  • ice jams
  • high lake levels or storm surges
  • heavy rains and thunderstorms

Floods can happen at any time of year, in both urban and rural areas. Flash flooding can occur when a storm drain is plugged — often with little or no warning.

Floods are the costliest natural hazard in terms of property damage in Ontario.

Before a flood

Be prepared for an emergency by creating a 72-hour emergency preparedness plan and kit for you and your family.

Inside your home:

  • Store personal belongings in sealed bins.
  • Move documents and keepsakes out of the basement.
  • Test sump pumps regularly and install a back-up power system (for example, battery back-up or generator).
  • Put weather protection sealant around basement windows and ground-level doors.
  • Install check valves in sewer traps to prevent floodwater from backing up into the drains of your home.

Outside your home:

  • Extend downspouts at least 2 metres from your home to move water away from the building.
  • Remove debris that could present danger during flood events.
  • Secure outdoor furniture and items around piers, docks or boathouses.
  • Regularly maintain water drainage systems, such as weeping tile, culverts and ditches.

Helpful links

During a flood

Evacuate immediately if you are told by emergency officials to evacuate.

If an evacuation is not in place, consider the following safety precautions:

If you are indoors

  • Make sure necessary personal items (medications and important documents) are secured and easily accessible in case you need to evacuate.
  • Disconnect electrical appliances — do not touch electrical equipment if it is wet or standing in water.
  • Do not eat food that’s come in contact with flood water.
  • Ensure your cellphone is charged (safely) — it may be your only means of communication during an evacuation.
  • Do not use taps, showers and toilets if your septic tank or the septic tank disposal field is under water.

If you are outdoors

  • If your property is impacted by flooding:
    • and your electricity is on, leave the area immediately
    • follow your emergency plan and move to a safe place on higher ground
  • Avoid travelling on roads that are near water, bridges, ravines, embankments, low laying areas and any bodies of water.
  • Do not drive through, stand or walk in any moving water.
  • If you must walk, look for where the water is not moving and use a stick to check the ground in front of you.
  • Account for all your family members, keeping children and pets away from floodwater.

Helpful links

After a flood

Before returning home, check with your local municipality for any information from your public health units, utilities and other community officials who are working to keep you and your family safe.

  • Don’t use flooded appliances, electrical outlets, switch boxes or fuse breaker panels until they have been checked by your local authority.
  • Follow instructions from your local public health unit when it comes to water in and around your home, which could be heavily contaminated.
  • Don’t eat food that’s come in contact with flood waters.
  • Contact your local municipality about debris management programs.
  • Report any broken utility lines to the appropriate authorities.
  • If your property has been damaged:

Helpful links

Flood forecasting and warning program

Visit the Flood Forecasting and Warning Program page to find:

  • a map of local and provincial flood messages (warnings)
  • information about the types of flood messages issued by the province, conservation authorities and other agencies
  • who to contact for more information about local flood messaging and on-the-ground flood response
Ontario flood forecasting map

Ontario flood map

Important contact information