How Long Does Sewage Contamination Last? [Answered]

During the research on how long does sewage contamination last, the substances are tested, sewage sludge, water, soil, and manure. The results are finalized, and they will discuss in this article.
Sewage sludge is a complex mixture containing a whole range of materials present in the wastewater discharged from domestic and commercial sources.

We will discuss how long sewage contamination will last on different surfaces.

How Long Does Sewage Contamination Last

How long does sewage contamination last?

Below is the table of how long the contamination last on different surfaces.

Bacteria OrganismSurfaceContamination Last
E. coli H37Soil17 Weeks
Escherichia coliLettuce28 Days
Escherichia coliWater103 Days
EnterococcusDry Surface27 Hours
Staphylococcus aureusHospital dry surface12 Days

These are the substances and contamination periods that are tested. Other substances that are not mentioned can also have different contamination periods.
Bacterial decay (death) rates can be affected by many factors. One factor is the bacteria’s environment (moisture, nutrients, salinity). Other factors include:

  • Temperatures
  • Micro-organisms that live in or on the decaying substance
  • Chemicals are released into the water during decay

The bacterium Escherichia coli (E.coli) often has zero decay after 24 hours, but some subtypes of E. coli are known to decay within 4-8 days at 20 degrees Celsius.

How long does sewage contamination last in the sea?

When sewage contamination is in the sea, the sewage will not last very long. Once it gets to the sea, sunlight and bacteria will break down any pollutants.

How long does sewage contamination last in a landfill?

A landfill’s contents are completely isolated from atmospheric oxygen or air. Organisms that break down wastes need air to survive. Sewage will decompose quickly in landfills. It will be safe to use in about six months.

How long does sewage contamination last on grass?

Covered with concrete, the sewage sludge will not even come into contact with soil or grass. If it is an open rain garden, though, there is a chance that some of the sludge may mix with the soil. Sewage contamination on grass will last up to 18 months, but this depends on how much sewage is present.

How long does contamination last in your home?

Bacteria can grow at room temperature and moisture level if they are exposed to oxygen (aerobic bacteria) or without oxygen (anaerobic bacteria). This can cause foul odors that will make your home less desirable to live in. Some people who are sensitive to chemicals may feel ill after exposure to sewage contamination indoors.

The sewage contamination lasts longer if it is not dried, like on a wet carpet or basement floor. It may take several years for the sewage contamination to dry out and evaporate.
When the sewage is mixed with water, for example, in a flooded basement or sewer backup, it can last months or years. Sewage contamination may go away on its own after several years of standing water, though.

However, if sewage contamination reaches your home through the groundwater, you should not wait for nature to take care of it. You are advised to get it removed as soon as possible.
The bacteria in the sewage will start dying in a few hours and will be no more in days. The contaminants that caused the smell and color of the water need much longer to dissipate, though.

How long does it take for sewage to decompose?

Sewage contamination will decompose within a few days, but this depends on the type of sewage present. Sewage can contain feces, human wastes, kitchen wastes, and cleaning chemicals that are toxic to plants and animals.

For example, all sewage is considered contaminated with salmonella bacteria. It can take months for salmonella to decompose in dry soil, but salmonella can die in a few hours in seawater or saltwater.
There are about 200 types of E. coli bacteria present in the human gut.

These do not have any smell, so many people confuse them with non-pathogenic forms of E. coli that reside on plants’ roots and insects.

The E. coli bacteria survive in moist environments for over a week but only last days if exposed to sunlight or seawater.


There are many factors that determine how long sewage contamination lasts. The environment the sewage is in, the bacteria present, and chemical reactions all play a part.

Sewage contamination can take months or years to go away if it is not dried out but will decompose quickly once it comes into contact with seawater or sunlight.



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