Environmental Health

Power Outages and Public Health

Emergency situations such as floods, forest fires or storms can sometimes lead to power outages. If these power outages last more than a few hours public health issues can develop.

Drinking Water

Power outages can cause problems for water treatment systems. You may have reason to believe that your drinking water has not been properly treated. Here are three ways to protect your drinking water:

  • Bring water to a rolling boil for one minute
  • Drink bottled water
  • Add 1/4 teaspoon of plain bleach to one litre of water, stir and let stand for 30 minutes before consuming.

Food Safety

Power outages prevent refrigerators and freezers from working properly. The food will not last very long under these conditions. Bacteria will start to grow when the food is warm. Here are some facts and tips on how to handle food safely during a power outage:

  • Keep the refrigerator and freezer doors closed as much as possible
  • A refrigerator can keep food cold for 4 hours
  • A freezer that’s half full can keep food cold for 24 hours but a full freezer can keep food cold for 48 hours
  • If the refrigerator gets warm, move the food to a cooler with ice or to a cooler location

After a period of time, it may be necessary to discard food. Harmful bacteria may have grown to levels that could cause you to get sick. Here are some tips to help you decide when to throw food away:

  • Use a thermometer to check foods:  refrigerators normally keep food at 4°C (40°F) and freezers normally keep food at -18°C (0°F)
  • Keep food in the refrigerator if it is still cold to the touch
  • If food in the freezer still has ice crystals it can be refrozen
  • Just because food looks and smells alright does not mean it is safe
  • When in doubt throw it out

Cold Weather

When a power outage occurs during cold weather:

  • Check for frozen pipes: damage to pipes can cause leaks which can lead to water damage and mould issues
  • Most heat sources require electricity to operate: ensure that alternate heat sources are safe and properly ventilated; otherwise, fatal carbon monoxide poisoning could occur
  • If you have no heat source, find a heated place to stay; staying in a cold environment can cause hypothermia , which can be fatal if not treated in time


Evacuations sometimes occur along with power outages. When you return home check the following:

  • Garbage may be rotten; to avoid attracting pests dispose of the garbage immediately
  • Check for frozen pipes (see above)
  • Refrigerated and frozen food may need to be discarded (see above)

Visit the Government of Canada’s website to learn more: