MSU Extension Safe Food & Water

In the event of a flood, floodwater and standing water can be dangerous to you and your community, and put you at risk of injuries, infectious diseases and chemical hazards according to the U.S. Centers for Disease Control and Prevention. It is important to know how to protect the food and water in your household from the dangers of floodwater, which can contain biological, chemical, and physical contaminants that can cause illness.

Prepare Before a Flood

Before a flood, there are some steps your family can take to be prepared in case of an emergency according to the U.S. Food and Drug Administration. In your home, store food, water and medication on shelves away from floodwater. It is also good practice to have an emergency kit prepared. In this kit, have a three-day supply of shelf-stable foods that don’t require cooking or water to prepare. These foods should meet the needs of infants, people on special diets, and pets in your household.

Store at least three gallons of water per person and per pet, for a three-day supply. In your emergency kit, also include unscented, household bleach; a dropper and/or a measuring spoon set; and empty quart, gallon, or liter containers to disinfect drinking water if necessary. Consider replacing the bottle of bleach every year and monitor the expiration dates of your store-bought water and shelf stable foods. Also include a battery-operated flashlight, extra blankets, can opener, basic first aid supplies, battery operated radio, and extra batteries in your kit per Ready.gov. Store this emergency kit on shelves, and away from heat sources and petroleum products preferably in a cool, dry, dark place according to Foodsafety.gov.

During a Flood: How to Treat Drinking Water

Know how to treat water to make it safe for drinking, cooking and personal hygiene in case of a water main break or flood. According to the U.S. Centers for Disease Control and Prevention, if you think your water is unsafe do not use that water to drink, wash dishes, brush your teeth, wash your hands, wash or prepare food, prepare baby formula or make ice. Note that it is impossible to make water safe that contains fuel, radioactive materials or toxic chemicals. If this is the only water available to you, contact your local health department for advice.

If you don’t have safe bottled water, the best way to treat water is by boiling it. If the water is cloudy, use a clean cloth, paper towel or coffee filter to filter the water first. You can also let the water settle and scoop off the cleaner water from the top. Then, bring the water to a rolling boil for one minute. If you are more than 6,500 feet above sea level, boil it for three minutes. Let the boiled water cool, then store it in covered, clean sanitized containers. You can make the boiled water taste better by pouring it from one container to another and letting it sit for a few hours, or add a pinch of salt to each quart or liter of water.

You can also disinfect water with unscented household chlorine bleach to make it safe to drink, but this does not work as well as boiling because it does not kill certain germs, including the parasites cryptosporidium and giardia. First, if the water is cloudy filter it or let it settle in the same way you would for the boiling water method. Follow the bleach bottle’s directions for disinfecting water for drinking. If there are no instructions, check the label for the bleach's concentration of sodium hypochlorite. Use the tables below to add the correct amount of bleach to quantity of water. Stir the mixture well, and let it stand for 30 minutes before you drink it. Store the water in covered, clean sanitized containers.

This table from U.S. Centers for Disease Control and Prevention shows how to use bleach to disinfect drinking water:

After a Flood: Cleaning, Sanitizing, and Salvaging Food

It can be overwhelming to clean up the aftermath of a flood but knowing what steps to take before an emergency happens can make the process a little easier. Food contact surfaces and equipment will need to be cleaned and sanitized after flooding.

According to the U.S. Food and Drug Administration, wear gloves when cleaning and sanitizing to protect your skin from irritation or infection. Throw out wooden cutting boards, wooden dishes and utensils, plastic utensils, baby bottle nipples, and pacifiers that have been exposed to flood water because they cannot be safely cleaned. For everything else, including metal pans, ceramic dishes, and utensils wash the items and the countertops with hot, soapy water and rinse them. Prepare a sanitizing solution of one tablespoon of unscented household liquid bleach (5.25%) per gallon of drinking water. Then, soak the utensils and equipment in the sanitizing solution you made for 15 minutes. For the countertops, apply your sanitizing solution and allow them to air dry.​ Run your empty dishwasher for three complete cycles to flush the water lines before using your dishwasher for dishes or equipment.

When it comes to the food in your pantry and cupboards, there are specific guidelines to follow from the U.S. Food and Drug Administration and Foodsafety.gov. It is important to throw out any food that may have come into contact with floodwater, especially food not in waterproof containers, food in cardboard containers, and home canned food. However, commercially canned food and food in retort packaging (pouches made of plastic and metal, that tuna is often sold in, for example) can be salvaged. Remove any labels on the package, if possible, and write down the expiration date and contents on paper so you can remember it to add back to the package later. Brush away any dirt, wash the cans/pouches with hot, potable soapy water and then rinse. To sanitize the cans and packages, either put them in a solution of one cup unscented household bleach and five gallons of water for 15 minutes, or put them in a pot of water, bring to boil, and boil for two minutes. After, write the contents of the cans and the expiration date on the package with permanent marker.

Preparation can help you better manage your family and household in the event of an emergency or flood, so consider assembling your emergency kit today and keeping this article printed with your kit. For other articles on staying food safe during emergencies please visit Michigan State University Extension’s Food Safety During Emergencies website.