Sewage Backups After a Flood

Homeowner Guidance for Sewage Backups After a Flood

Sewage backups not only present unpleasant odor problems but may also cause property damage and present unhealthy living conditions. Untreated sewage contains disease-causing organisms such as bacteria, viruses, and parasites. Contact with contaminated water can cause skin infections and rashes. If ingested accidentally via improperly cleaned hands or food preparation surfaces, these contaminants can cause nausea, abdominal pain, vomiting, and diarrhea.

Sewage Health Risks

Mold growth associated with wet and humid conditions may also result in respiratory infections and allergic reactions. The drying out process can take several weeks in an enclosed area such as a basement or crawl space, and microorganism growth will continue as long as the humidity remains high. If the damaged area is not cleaned and dried out properly, a musty odor can remain long after the sewage overflows.

Contaminated Materials Outside the Home

If there is a broken sewer line outside the home or in a crawl space under the home, the first step to cleaning it up is to put on protective clothing such as:

  • Waterproof boots
  • Gloves
  • Eye protection
  • Clothes that are either washable or disposable
  • N95 masks to avoid breathing airborne microorganisms

Contaminated Soil

Plastic ground liners, surface contamination, and heavily contaminated soil should be removed from the impacted area if possible. When removed, contaminated soil should be disposed of in an approved landfill. The remaining contaminated soil should be treated in place with a liberal application of garden lime to reduce odor and enhance the degradation of the organic matter.

If the contaminated area is in the open, it should either be covered with clean dirt or temporarily fenced off to prevent accidental contact with the lime and any remaining contamination. After a day or two, mix the lime in with a rake and use a sprinkler or hose to water the lime and any remaining residues into the soil. Prevent any water or soil from entering stormwater by containing it onsite or disposing of it in an approved landfill or approved wastewater dump station. Let the area dry in the sun, if possible, before allowing access.

Excavated soils may be remediated onsite by treatment with garden lime, which should be turned over frequently to provide oxygen to the naturally occurring microbes in the soil that degrade the organic material. If onsite treatment is not possible or cannot be accomplished without creating a nuisance condition, contaminated soils and other materials removed from the impacted area may be disposed of at any landfill willing to accept them.

Contaminated Materials in the Home

Sewage-exposed materials must be thoroughly cleaned and disinfected to reduce the risk of disease.

  • Put on protective clothing, as noted previously.
  • Lower the humidity by opening up the house and removing standing wastewater with a mop, wet vac, or squeegee.
  • Open closets and cabinets to allow circulation.
  • Circulate the air using fans, dehumidifiers, and window air conditioners. However, only use whole-house air conditioners or furnace blowers if standing wastewater does not impact the air ducts.
  • Purchase moisture-absorbing products from home repair or lumber stores and place them in enclosed areas where air can’t move through.
  • Sort the contents of the damaged area to separate salvageable furnishings from unusable debris.
  • Throw away contaminated mattresses, pillows, foam rubber items, upholstered couches, and chairs, books, and most paper products because they soak up contamination and are difficult to disinfect.
  • Hire a professional cleaning company to steam clean and disinfect salvageable furnishings that were exposed to wastewater that cannot be thoroughly steam cleaned or disinfected.
  • Dispose of materials that were exposed to the wastewater that cannot be thoroughly steam cleaned or disinfected.
  • Discard all potentially contaminated food items, cosmetics, stuffed animals, and baby toys.

Washing Soiled Items

When in doubt, throw it out.

Soiled clothing and small throw rugs should be thoroughly washed in warm or hot water, with bleach if possible. Discard more oversized rugs and those with foam backing.

After getting wet, wall-to-wall carpeting usually does not return to its former size and has to be thrown away. If only a portion of the carpeting is damaged, a professional carpet cleaner may adequately clean it. However, the foam padding will likely have to be replaced.

Preparing Items for Disposal

Discarded items should be sealed in heavy plastic garbage bags before disposal. Your trash collection company should be contacted about removing furniture and bulky furnishings, or the homeowner can take these items directly to a landfill.

Homes with Minimal Damage

If there is minimal damage to the home and the overflow can be cleaned up promptly, then the damaged area may simply need to be cleaned and disinfected. This involves thoroughly washing and disinfecting the walls, floors, closets, and other washable contents of the damaged area.

In most cases, everyday household cleaning products and disinfectants will do the job if used correctly. Disinfectants and sanitizers often contain toxic substances, so be sure to read and follow all label instructions carefully. Be careful about mixing household cleaners and disinfectants since some can produce harmful vapors. For example, mixing bleach and ammonia forms the toxic gases chloramine and ammonium chloride.

Air Circulation

Fresh air should always be provided by opening windows and doors and using fans to circulate air both during and after the use of disinfecting, cleaning, and sanitizing products. A mixture of one-quarter cup of chlorine bleach in 1 gallon of water is an effective and readily available cleaning solution. This solution should be kept in contact with the item to be cleaned for at least one minute. After an item is cleaned in such a manner, it should be rinsed well, gone over again with mild soap and water, and thoroughly rinsed again. Since most fabrics can’t be cleaned with bleach without fading, they may instead be cleaned with a quaternary ammonia product such as Lysol.

Homes with Extensive Damage

If the damage was extensive or the overflow could not be cleaned up promptly, removal and replacement of damaged wallboard and wall insulation should be considered to avoid indoor air quality problems later. The wallboard acts like a sponge, drawing moisture up above the water level. It becomes very fragile if it stays wet for long and will fall apart when bumped. If asbestos-containing materials are known to be present in flood debris in amounts more significant than regulatory trigger levels, they must be removed in accordance with Colorado Air Quality Control Commission Regulation No. 8, Part B.

Even if the area is dried out, contaminants may have gotten up behind the drywall and dried inside. Mold can penetrate deep into soaked, porous materials such as wood, insulation, and drywall and continue to damage these materials long after the overflow event is over. Even after everything has dried out, microorganisms can later be released into the air and trigger allergic reactions when inhaled.

Wooden wall studs and sills probably won’t need to be replaced if they are thoroughly cleaned, disinfected, and allowed to dry properly. Since the studs and sills will be covered by new wallboards and painted, they will be removed from direct human contact. If the walls are paneled, the bottom of each panel should be carefully pried away from the wall. A block or something similar should be used to hold the paneling bottom away from the wall sill so that the area between wall studs can drain and dry out. The paneling may have to be removed entirely to remove any wet insulation or extensive contamination behind it. Once disinfected and dried out, the paneling can often be nailed back into place. Wastewater won’t damage concrete like it will wood or wallboard, but it will still soak in to some extent. Concrete walls and floors should be washed thoroughly and allowed to dry out.

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