DPH: Post Flood: Key Facts About Infectious Disease

Post Flood: Key Facts About Infectious Disease


Even though widespread outbreaks of infectious disease after floods are not common in the United States, it is still important to protect your health. Rare and deadly exotic diseases, such as cholera or typhoid, break out after hurricanes and floods only in areas where such diseases occur naturally. These diseases do not occur naturally in Connecticut. Common stomach (gastrointestinal) and breathing (respiratory) problems are more likely after natural disasters because clean water may be hard to find. This makes cleaning your home thoroughly, finding good drinking water, and using clean water for hand washing, bathing, and washing dishes very important.


Am I at risk for getting sick from flood water?

Flood waters contaminated with sewage can pose a risk to your health if swallowed. Stomach illnesses such as vomiting and diarrhea are the greatest risk from swallowing contaminated water. Direct contact with contaminated flood water can cause skin rashes or infected cuts and wounds. Breathing problems can worsen if sewage is allowed to dry and becomes airborne.


How long am I at risk?

Low levels of some infectious agents are present in the environment normally and can remain slightly elevated for several months after a flood. Bacteria, viruses, and parasites can survive on outdoor hard surfaces, grasses and in soil after sewage contaminated flood waters have retreated. The amount of time they can survive depends on factors such as temperature, humidity, acidity of soil, and amount of sunlight. Sunlight and higher temperatures help kill them, and rain waters help flush them from the soil. Avoid these areas until they have dried and sewage is no longer visible.


What can I do to decrease my chances of getting sick?

To decrease your risk of getting sick:

  • Clean up any visible sewage and all outdoor hard surfaces exposed to flood waters as you would indoor surfaces – see Sewage Back-Ups: Information for Residents
  • Wear protective eyewear, gloves, and boots
  • Wear goggles when hosing off items to prevent eye splash
  • Avoid direct contact with sewage
  • Wash your hands after cleaning
  • Protect all cuts and scrapes. Immediately wash and disinfect any wound that comes into contact with sewage
  • Never mix bleach with ammonia – it makes a deadly gas!
  • Wash the affected area with detergent solution to remove surface dirt and contamination. (Don’t skip this step, or the disinfection step will be ineffective!) Allow it to air-dry. Apply a disinfectant labeled as being bactericidal (kills bacteria) or a bleach solution (see Centers for Disease Control and Prevention (CDC) bleach solution recommendation). Disinfectants and/or bleach should remain in contact with the area for 15-20 minutes to be effective. Allow the area to air-dry again.
  • Throw away seat cushions or other soft porous objects that could have been soaked by sewage. 

Is it safe to eat foods from my garden or continue to do gardening?

Gardens that have been flooded by waters contaminated with sewage or chemicals are considered unsafe. Do not eat food from these gardens. And do not work in them immediately after the flood.

  • Discard all fruits and vegetables from gardens that came in contact with flood waters or flood water-soaked soil. Even if the produce looks okay, it is contaminated, and eating it increases your chance for getting sick.
  • Avoid digging in soil for several weeks. Infectious agents and chemicals from flood waters can be found deeper in the soil and take longer for nature to remove because they are exposed to less sunlight and are less affected by temperature. If you must dig, take special precautions like wearing gloves, goggles, and boots.  

Is it safe to have our children and pets play in the yard after the flooding is gone?

Yards that were affected by flood waters with sewage are also contaminated.

  • Children should not be allowed to play in yards affected by flood waters until nature has had time to kill any germs. 
  • Allow the yards to be dry completely and be exposed to sunlight.  Shaded areas may take more time for the germs to be killed.
  • Wash hands and soiled skin often and protect cuts and scrapes.
  • Clean your pet’s fur and paws with soap and water before bringing the pet indoors. Use liquid dish soap or hand soap just as you would wash your own hands.  

Is it safe to mow my lawn?

Do not mow or trim your lawn until any contamination has been cleared and nature has had some time to kill or remove germs with sunlight and rain. Use a mask while cutting the lawn or doing any yard work. If you have any breathing problems such as COPD, emphysema or asthma, ask your doctor about the risks of performing these activities and wearing a mask.


My immune system is weak already due to illness or medication; am I at increased risk of getting infections after a flood?

Persons with weak immune systems (such as those undergoing cancer treatments or on long term steroids) should take additional precautions to avoid contact with sewage or sewage-contaminated areas. Consider avoiding contaminated areas until they can be cleaned and disinfected by friends, family, or possibly a professional (see Sewage Back-Ups: Information for Residents).


Do not touch your eyes and mouth after touching potentially contaminated surfaces including yards and soil. Wash your hands thoroughly after contact, and protect open cuts and scrapes by covering them.   


I have other concerns about the flood such as my drinking water, chemicals in flood water, food safety, and mold.  Where can I learn more?

Additional Information can be found on the Connecticut Department of Public Health (DPH) and the CDC websites:



Flooding: Information for Homeowners About Private Wells, Sewage and Clean-Up

Sewage Backups: Information for Residents

After the Storm:  What to Do When You Go Back to a Flooded, Moldy Home

Private Wells



Emergency Preparedness and Response: Floods

Returning to your home after the flood

Keep Food and Water Safe After a Disaster or Emergency

Protect Yourself from Mold

STORM, FLOOD, AND HURRICANE RESPONSE: Recommendations for the Cleaning and Remediation of Flood-Contaminated HVAC Systems: A Guide for Building Owners and Managers

Protect Yourself From Chemicals Released During a Natural Disaster


If you have any additional questions or concerns, please contact your doctor. For more information, call your local health department or the Epidemiology and Emerging Infections Program at 860-509-7994.



This fact sheet is for informational purposes only. It should not be used for self-diagnosis or as a substitute for consultation with a health care provider. If you think that you may have this infection, or have questions about the disease described above, you should consult your health care provider.

Content Last Modified on 7/12/2016 3:18:51 PM