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How Does Water Affect Human Body Decomposition

Updated: Apr 12

How Does Water Affect Human Body Decomposition Graphic

Handling a dead body is one thing, but dealing with a body that has already started the decomposition process is another. And if said body has begun decomposing in water, you'll find that it is a touch more complicated.

The condition of a decomposing body in or exposed to water differs from that of a body in a dry environment. The natural process of decomposition will happen at a slower rate in water.

Let's explore exactly how water affects a person's decomposing body and what causes this to happen.

What Happens When A Body Decomposes In Water?

 A body that has been submerged in water tends to have a slower decomposition process due to the cooler temperatures and anaerobic environment. However, some stages of decomposition, such as algor mortis (the lowering of body temperature), will happen sooner if the body decomposes in cold water.

To understand the effect water has on decomposition, you must first look at the typical decomposition changes that happen when human bodies decompose.

The five stages of typical decomposition

  1. Cell autolysis or self-digestion - 24-72 hours after death

  2. Bloat - 3-5 days after death

  3. Active decay or putrefaction - 7-10 days after death

  4. Advanced decay - 2-3 weeks after death

  5. Skeletonization - one month to a year after death

Given that there are many variables to consider regarding a body decomposing in water, it is often difficult to determine an exact timeline for the rate of decomposition.

If the water is cold with no predatory activity or currents, a body may remain completely intact for weeks or even months.

In comparison, remains that have been submerged for two weeks are equivalent to a body on dry land that has been decomposing for one week. The body will endure all the typical changes of decomposition, such as darkening of the soft tissue and skin, vascular marbling, and bloating, but at a slower rate.

External factors that affect the rate of decomposition

As with typical decomposition, the factors listed below are also relevant to bodies that decompose in water:

  • Temperature

  • Oxygen

  • Humidity

  • Weather

  • Moisture

  • Scavengers

  • Insects

  • Wildlife

  • The size and weight of the body

Looking at the factors listed here, it is easy to understand that there would be a significant impact on the decomposition of the human body when in water. Exposure to moisture and water can accelerate decomposition - the opposite of a body being immersed or fully submerged.

The putrefaction stage, for example, ideally occurs at temperatures above 50°F and ceases below 32°F. This stage also happens more rapidly in warm freshwater and stagnant water compared to cold saltwater. Putrefaction is delayed even further when a body is deeply submerged and protected by clothing.

Factors In Water That Affect Decomposition

Recovering bodies from water is not uncommon. However, there are factors specific to certain bodies of water that will further impact decomposition.

Water temperature

Cooler temperatures slow the typical decomposition process. The bacterial growth slows, which delays the bloating stage of decomposition. When human bodies decompose in cold water, the formation of adipocere happens faster.

This is a typical occurrence on remains that have been exposed to moisture. Adipocere is a waxy soap-like substance that forms by the hydrolysis of the fat in human tissues. This substance acts as a partial protection barrier against decomposition.

A warmer water temperature will speed up the decomposition of the human body, as the environment is ideal for microbial activity during the bloating phase. For this reason, remains submerged in warm water will not stay fully submerged for very long.

Even a weighted body will resurface due to bloating within 3-4 days, when it becomes exposed to other environmental factors that affect human decomposition.

Type of water

Human body decomposition will vary depending on the type of water in which it has been submerged. Remains submerged in saltwater tend to decompose slower than those in freshwater.

The salinity, acidity, and alkalinity of the water affect decomposition. Salt and acidic water will slow the process with the latter having a preservative-like effect on the human tissue. In contrast, water with a high alkalinity will increase the rate of decomposition.

The water currents would also need to be factored in as this could move the human remains and cause physical damage and accelerated sloughing of the tissues and skin.


As discussed, the submersion of human remains in water makes for a slower decomposition process. Decomposition rates will vary between immersed and fully submerged remains. For example, if a person dies in a bathtub or shallow water, the body is only partially submerged.

In a bathtub, for example, there may be varying degrees of decomposition to the parts of the body that are immersed in the water compared to those left exposed to the air.

In shallow waters, parts of the body, such as hands, knees, and feet, may drag along the floor of the area of water as the midsection becomes more buoyant and rises to the surface. This causes abrasions and scrapes to the dragged skin and sometimes affects the determination of the cause of death.

Significant wildlife factors nearby

While a human body decomposes slower in water, wildlife in and around the area may alter the rate of decomposition. Scavenging creatures may feed on immersed and submerged remains. Fish, crabs, and turtles can feed on the soft tissue of the body while sea birds and insects feed on the areas that are exposed if the body floats to the surface. For this reason, rapid skeletonization may occur.


If a person is fully clothed, and in water, the clothing will affect the buoyancy of the body. This means that it might take a bit longer for the body to resurface. Likewise, the clothing could become entangled keeping the body trapped below the surface. Once the bloating stage has occurred, clothing will likely become ill-fitting or give the appearance of a previous struggle.

What Happens When The Body Is Removed From Water

When a body is removed from the water within the first three stages of decomposition, the putrefaction stage happens at an accelerated rate. This is a direct impact of the sudden change in temperature, moisture, and the shift from an anaerobic to an aerobic environment.

Effects on autopsy and determination of the cause of death

For a forensic pathologist or medicolegal death investigator, human remains that have decomposed in water are not uncommon. They do, however, need to work quickly, especially if foul play is suspected. The condition of this type of body can often mimic signs of struggle or foul play.

This is due to the sometimes erratic and boisterous nature of the water such as the abrasions caused by immersion in shallow water. These experts recognize such anomalies and take them into consideration when determining a cause of death.

What To Do If You Discover A Decomposing Body In Water

If you have unfortunately discovered a body that has been decomposing in water, your first step is to call the authorities and move away from the scene. Do not touch the body or disturb the surrounding area and water. No matter what stage of decomposition the body is at, the area is now considered a crime scene as well as a biohazard.

Once the body has been removed, professionals will need to be called to conduct biohazard decontamination. This is especially important if such an event has occurred within a household.

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