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During and after a flood event, usually the last concern is future problems that the flood damage may cause. While it is extremely important not to re-enter the building until flood waters recede, it is important to remember that cleanup should begin as soon as it is safe to return to the building.

Prompt and proper cleanup is important for your health. Flood waters can contain microorganisms, such as bacteria and molds, viruses, raw sewage, dead animals and other debris. It is important to remove such debris and/or contaminated materials from your home as quickly as possible to eliminate possible or continued microbial growth. Poor indoor air quality can result if materials are not cleaned properly or discarded promptly and can lead to ongoing contamination of your indoor air by the microorganisms mentioned above. Poor indoor air quality can lead to various health issues including respiratory problems and allergies, and it can continue to damage building materials long after the flood waters have receded.


Remove water:

As soon as possible, all water should be pumped, swept, or otherwise removed from inside of the building. Any debris, such as tree branches, garbage, and mud, should also be removed at this time. It is also a good idea to remove furniture, carpets, and other items that were wet or damaged by the flood waters. These materials, once wet, may contain contamination, such as microbial growth. By removing the wet or damaged materials that may contain health hazards, you are effectively removing the microorganisms. This is also the time when leaky roofs, broken windows, or other areas where water may leak into the home should be patched or fixed to eliminate possible future water damage.

Completely dry out your house/building:

The next step is to thoroughly dry the building. This process should include the use of fans if it is safe to use electricity and the opening of windows to increase air circulation, ventilation and drying. Dehumidifiers should be used with windows and doors closed. It may be necessary to remove portions of walls, ceilings, and floors to fully accomplish a complete drying out of the house. Certain building materials (for example, wallboard, fiberglass, insulation and wall-to-wall carpeting) that were soaked only with clean rain water may be able to be saved if dried properly and completely. You may, however, want to consider removing and replacing them to avoid possible future indoor air quality problems, especially if the beginning of the drying process was delayed for more than 48 hours. The drying process is extremely important because many of the microorganisms, which can cause health effects, need moist environments to survive.

Time is very important:

As mentioned before, prompt action is very important for proper drying. Drying can usually be successful during the first 24 to 48 hours following water contamination. After that time period, removal of wet materials is usually the best option. The microorganisms that are found in flood waters can establish themselves very quickly and once established, they may be hard to eliminate. The drying process should continue for days to weeks until materials are thoroughly dry (not just to the touch) and humidity levels return to normal (35-55%). Humidity levels are important to monitor, since the growth of microorganisms will continue as long as humidity levels are high. If the house is not dried properly, a musty odor, signifying growth of microorganisms, can remain long after the flood.

Clean all surfaces:

The walls, floors, studs, closets, shelves, contents, in fact, every flooded part or item in your house, should be thoroughly washed and disinfected. Bleach, mildew removers, disinfectants such as quaternary, phenolic, or pine oil based cleaners, and non-sudsing household cleaners should be used. It is important to read the label on every cleaner and use the appropriate safety methods. This includes such things as wearing gloves, eye protection, providing proper ventilation and not mixing different household cleaning agents. Mixing certain types of products, such as bleach and ammonia, can produce toxic fumes and result in injury and even death. As household cleaning agents contain chemicals that may be harsh, care should be exercised when cleaning items.

Remove and discard items that can not be dried and cleaned effectively:

It can be difficult to throw away items in a home, particularly those with sentimental value. However, keeping certain items that were soaked with water may be harmful to your health. As a general rule: Materials that are wet and cannot be thoroughly cleaned and dried should be discarded, as they can remain a source of microbial growth. In addition, fiberboard, fibrous insulation and disposable filters in your heating and air conditioning system should be replaced if they are in contact with water. The heating and air conditioning ducts will also need to be cleaned if they contacted water.

Avoid carbon monoxide danger:

Carbon monoxide (CO) is a colorless, odorless, gas that can be lethal at high levels. Carbon monoxide levels can build up rapidly if certain types of combustion devices (for example, gasoline-powered generators, camp stoves and lanterns or charcoal-burning devices) are used indoors. Do not use combustion devices designed for outdoor use indoors.


  • Copies of this fact sheet are available from the Environmental Health Evaluation Branch of the Delaware Division of Public Health.
  • A publication called Repairing Your Flooded Home, is also available from the American Red Cross and the Federal Emergency Management Agency (FEMA).
  • Information on many aspects of indoor air quality is available from the US EPA.


  • Repairing Your Flooded Home.  American Red Cross/Federal Emergency Response Agency (FEMA).
  • USEPA. Indoor Air Quality Information. P.O. Box  37133, Washington, DC 20013-7133
  • Adapted with modifications from American Red Cross/FEMA and U.S. EPA Fact Sheets and Reports.

Content Revised: July 12, 2004