Sewer Backups or Flooding, How to Clean Up After One

sewer backup

The other day we put up a post on the problems of sewer backups that can be caused by a major disaster or flooding.  Remember that after a major disaster or disruption of services that many of the flood control systems may cease to function.  This includes pumping stations and even dam failures.

The following is information that may help you cleanup if you are affected by either flooding or sewer backups.

Cleanup of Internal Areas after a sewer backup or flood

Once the floodwaters have receded and the property can be accessed safely you should begin cleanup.  The most important steps are to restore the environment to a dry state and salvage any valuable property.  The longer that water/waste are allowed to remain in your home or on your property, the greater the potential for illness and irreparable damage to your home and its contents. If you have the use of pumps and dehumidifiers, they will be helpful in restoring dry conditions. In any sewer backup or flood cleanup project regardless of the source, one should assume that pathogens are present and take appropriate precautions.

The survival of pathogens depends on a number of factors: location (indoors vs. outdoors), season, type of surface contaminated, whether disinfectants are used, and also on environmental conditions such as humidity, temperature, and sunlight.  Sunlight (UV radiation) reduces the survival rate of pathogens with numbers decreasing rapidly with increasing exposure to UV radiation.  Mild temperatures and higher humidity in external situations result in longer survival times.

Prior to undertaking cleanup efforts, protect yourself:

Always wear protective gloves, eyewear, and boots.  Rain gear is also advisable.  Avoid direct contact with sewage material, and be particularly careful of your face and eyes. Goggles are recommended when using a hose and/or any chemicals.  Protect all cuts and scrapes. Immediately wash and disinfect any wound that comes in contact with sewage.

The following steps should be taken to mitigate the microbial risk from a building contaminated by a sewer backup.

  • Any excess water should be removed from the property by pumps, wet vacs, or mopping. Dehumidifiers and active ventilation should also be used when available.
  • All solid waste should be collected and disposed.
  • All upholstered furniture and mattresses should be discarded, other contaminated furniture should be removed and cleaned or discarded.
  • The affected areas should be washed with a detergent solution to remove sewage-related contamination, then disinfected and allowed to dry.

Sort damaged contents into piles to be repaired or discarded. Use the following guide for discarding of household material and furnishings.

Usually Discard

  • Foam rubber
  • Large carpets
  • Books and paper products

Always Discard

  • Cosmetics
  • Stuffed animals
  • Toys
  • Mattresses and pillows
  • Upholstered couches and chairs
  • Carpet padding
  • Cardboard
  • Medicines and medical supplies, unless completely sealed in watertight containers and then properly disinfected.
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Food is always a problem because it may be in short supply. The following link is to a blog that we wrote on possible methods of savaging foods.


  • Assume anything touched by sewage is contaminated.
  • Clean and disinfect everything sewage has touched.
  • Always wear protective rubber gloves, eyewear, and boots and be especially careful if you have cuts or open sores.
  • Wash, disinfect, or discard any clothing and supplies immediately after use.


Disinfectants are typically chemical agents that reduce significant numbers of pathogens to levels below those expected to cause disease. Cleaning and disinfection are two different processes. Cleaning removes the dirt. The processes of disinfection and decontamination are important to ensure the elimination of pathogens and organisms that were contained in the sewage or that grew during the period of contamination. Even concrete can be colonized and broken down by microorganisms if it is allowed to remain wet and contaminated by organic matter.

Many household products are capable of disinfecting surfaces and should be used in accordance with manufacturer’s label directions. A household bleach solution is also an effective disinfection agent, and can be made by combining one quarter cup of household bleach to one gallon of water. Bleach should never be used directly without dilution since, in this concentrated form, the bleach can cause severe skin and respiratory hazards.

To prepare surfaces for disinfection, wash surfaces first with warm soapy water and rinse surface. Apply the disinfectant solution to all areas of the affected surface, and allow for sufficient contact and drying time.

When proceeding with cleanup operations, remember that those individuals whose immune systems are in some way compromised or who are otherwise susceptible due to age, medication, or underlying illness, are considered to be at greater risk of contracting infections than those individuals who are healthy.

Cleanup of External Areas

The majority of the microbial population from sewage backups onto lawns, tarmac and paved areas will be inactivated within several days due to exposure to UV radiation from sunlight. A disinfectant can be used on tarmac and paved areas. Contamination on grass could be left to degrade naturally. Typically, bacterial numbers on turf are reduced to background levels expected in the environment within 13 days, but can extend to 20 days on soil and sand in the autumn and spring. Generally, the least absorbent or pervious surfaces absorb the least sewer and bacterial concentrations and return to background levels the quickest.

After a sewer backup or flood, if things can be easily replaced get rid of them. After TEOTWAWKI, the problem becomes much harder.  Use your head and salvage what you can, but don’t make yourself sick by taking to many chances.


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5 thoughts on “Sewer Backups or Flooding, How to Clean Up After One”

  1. Good reminders on the pitfalls of flooding. One thing many folks forget about are appliances that are plugged in and standing water. We found that out many years ago. An electrical shock will impress this upon your memory very quickly.

    Also, I didn’t know that concrete could be broken down by microorganisms. Good info.


  2. You want to detect possible sewer backup before it gets into your home. It’s an unpleasant, stinky experience and can be very damaging. In our last home, the sewer would start backing up every 3 or 4 years because of the trees near our home. We eventually noticed the pattern and were able to take preventative measures. Just keep an eye out for any unusually slow drains.

  3. Good safety tips to avoid any spread of disease. A professional should really be in charge of dealing with sewage issues but you should follow these guidelines if you have no choice. Thanks so much for sharing.

  4. Just from the look of that picture, that sewage back up did a number on your house. It always scares me that my sewage will back up and wreck my home. After reading your article, I totally get why it is so imperative to wear gloves when cleaning up after a flood. There’s no telling what kind of diseases and problems are in that water.

  5. It doesn’t include the cost of hiring a plumber to fix the block in your line that caused the sewer backup in the first place. And it doesn’t include the costs of replacing any items that were removed during the cleanup process. When raw sewage touches porous surfaces, in almost all instances those surfaces will need to be removed and thrown away.

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