What Is Turbidity in Water: 11 Things (2024) You Have to Know

Have you ever looked at water that’s brown and murky?

You may even be able to see floating sediment.

If so, this water has high turbidity.

Turbidity describes the clarity of water, and it’s a critical factor in water quality.

Here’s what you need to know if you’re seeing lots of turbidity in water sources near you.

1. What is turbidity in water?

Turbidity is cloudiness or murkiness in water that’s caused by suspended or dissolved particles.

This particulate matter can include sediment like clay, silt, fine organic matter, inorganic matter, soluble colored organic compounds, algae, and other microscopic organisms.

Turbidity in water can cause issues and make drinking water unsafe.

If you’re experiencing high turbidity in your personal water supply, it’s important to recognize the risks and take steps to remedy it as soon as possible.

2. What causes turbidity in water?

Numerous factors cause cloudiness in water.

These include:


Phytoplankton are a type of microscopic marine algae.

They can turn water brownish-red when present in high concentrations.

Phytoplankton often float in water.

They can survive in either fresh or saltwater environments.

bulletSediments from erosion

Turbidity is often caused by sediment from erosion.

Picture a river flowing through an area of loose dirt.

It’ll pick up the dirt, and the dirt will seep into the water.

If the water is swift, then it can begin to erode tougher materials like rock, which will increase the sediment level in water.

This will increase the murkiness you see.

bulletResuspended sediments from the bottom

Sediment disruption occurs when water picks up a body of sediment and moves it to a new spot.

This increases the turbidity in certain areas.

A common area may be the pool of water beneath a waterfall.

In rivers, this sediment disruption can influence water flow and modify the water depth.

Additionally, resuspension of sediments can also come from bottom feeders like carp stirring up the sediments.

bulletWaste discharge

If wastewater isn’t properly treated and disposed of, it can carry pathogens, suspended solids, and other contaminants to a nearby body of water.

This will increase its turbidity as well as the human health risk.

Note: This water typically comes from pipes in factories and plants that treat wastewater.

Though the EPA has produced guidance on how to treat wastewater before dispelling it, many treatment locations still fail to follow these guidelines appropriately.

bulletAlgae growth

Algae is a group of organisms living in both freshwater and saltwater bodies.

You can find algae in numerous sizes and appearances.

Sometimes these organisms are too small to be seen by the human eye.

They may be rooted to the surface of the ground or floating depending on the type of algae.

The presence of algae in water can be negative.

It takes nutrients from the water and increases oxygen levels.

When algae die, the organic matter is released and increases turbidity in water.

bulletUrban runoff

Urban runoff is surface water from either rainwater or melted snow that can be responsible for pollution or contamination of water sources like private wells, lakes, and rivers.

Water running through agricultural or industrial sites will pick up sediment that increases the turbidity of the water source where it ends up.

This can even happen from water that travels across impermeable paved surfaces or building surface materials.

3. What are the primary impacts of turbidity in water?

bulletIt’s aesthetic

One of the primary impacts of turbidity is that it significantly reduces the aesthetic quality of lakes and streams.

This can have a negative effect on recreation and tourism because no one likes the way that murky water looks.

bulletIt’s harmful to aquatic life

High turbidity can harm fish and other aquatic life.

For freshwater fish specifically, here are the poor impacts it can have…

  1. Fine particles act directly on the fish by killing them or reducing their growth rate, resistance to disease, etc.
  2. Fine particles prevent the successful development of fish eggs and larvae
  3. Fine particles modify natural movements and migrations
  4. Fine particles reduce the amount of food available in water

In general, all aquatic life is negatively affected by high turbidity because it reduces food supplies, degrades spawning beds, and affects gill function.

bulletIt increases the cost of water treatment

With high turbidity, water must be treated more carefully.

This increases the cost of treatment because you’ll need to treat all water for both drinking and food processing.

4. How does turbidity affect water quality?

Turbidity indicates the number of suspended particles in the water, which can negatively affect aquatic life.

These particles can block light to aquatic plants, smother organisms, and carry contaminants like lead, mercury, and bacteria.

In terms of drinking water, turbidity is used to indicate the presence of pathogens, bacteria, and other contaminants.

Measuring turbidity before it’s used for human purposes is essential.

5. What impact does turbidity have on human health?

Turbidity can act as a shield for disease-causing pathogens.

When the water isn’t treated well, it can lead to waterborne disease which causes intestinal sickness.

Additionally, high turbidity in water makes chlorine treatment less effective.

While it isn’t impossible to treat water with high turbidity, it’s much more difficult and expensive.

6. What are the consequences of high turbidity?

The suspended particles in high turbidity water absorb heat from the sunlight.

This makes turbid waters warmer and reduces the concentration of oxygen in the water because oxygen dissolves better in cold water.

Additionally, some organisms are unable to survive in warmer water.

The suspended particles also scatter light which decreases the photosynthetic activity of plants and algae.

This can also prompt a lower oxygen concentration.

When the particles settle to the bottom, several disruptions can occur.

These include…

bulletShallow lakes fill faster

bulletFish eggs and larvae getting covered and suffocated

bulletGill structures getting clogged or damaged

7. How do you measure turbidity in water?

Turbidity is the measure of the degree to which water loses its transparency due to the presence of suspended particulates.

When water has more total suspended solids, it has higher turbidity.

It will appear murkier.

Today, there are state-of-the-art turbidity meters that are installed in rivers to provide instant turbidity readings.

In general, turbidity is considered a good measure of water quality.

These meters use a long device lowered into the water to measure the levels of total suspended solids (TSS).

TSS refers to waterborne particles that are larger than 2 microns.

These are the common culprits behind turbidity.

At the end of the device is a turbidity sensor that reads the turbidity in the body of water by shining a light into the water and sensing how much light is reflected at it.

These devices can also have multiple water-quality sensors, including conductivity sensors to measure the electrical conductance of water as well as temperature gauges.

The electrical conductance of water is strongly affected by dissolved solids.

When measuring turbidity in water, the unit of measurement is Nephelometric Turbidity Units (NTU) and comes in several variations.

8. How do you test your local water quality?

If you’re interested in testing your local water quality, there are water test kits available from World Water Monitoring Challenge (WWMC).

This is an international education and outreach program that builds public awareness and involvement about how to protect water resources around the world.

The test kits allow you to perform basic water-quality tests on local water for temperature, pH, turbidity, and dissolved oxygen.

9. What is the maximum turbidity that’s permitted in drinking water?

The World Health Organization (WHO) established that the turbidity of drinking water shouldn’t be more than 5 NTU.

Ideally, however, the turbidity should be below 1 NTU.

10. What’s the difference between turbidity and total suspended solids?

The turbidity of water and total suspended solids are similar, but they aren’t the same.

Here’s the core difference if you’re a bit confused.

Turbidity is the measurement of how transparent water is.

Suspended solids are the contaminants that are largely responsible for turbidity in water.

The higher the levels of total suspended solids (TSS) in water, the greater the level of refractions of light from these materials, and the higher the turbidity.

11. How do you remove turbidity in water?

Are you looking for some simple ways to remove turbidity in your water source?

Here are interventions that you can use to improve water quality and pre-treat water before using household water treatment products.

bulletCloth filtration

This is a simple and effective way to pre-treat turbid water.

You merely filter the water through a locally available cloth.

In most cases, the user will pour water from the transport container through the water into the storage container.


  1. Simple
  2. The wide availability of cloth
  3. Reduction of disease (filtration through multiple layers of sari cloth has been shown to reduce cholera transmission in countries like Bangladesh)


  1. Filtration capacity varies greatly
  2. Slow process
  3. Reduces the turbidity of water but not its chlorine demand (chlorine demand is the amount of chlorine that’s used up by organics before disinfection can occur)

bulletSand filtration

This is another fast and simple option to pre-treat turbid water.

To filter through sand, you pour water from a transport container through a container of sand with gravel and a spigot at the bottom.

The water will flow into a storage container.


  1. Effective at removing some bacteria
  2. Simple and fast
  3. Inexpensive if sand is available locally


  1. Requires three containers and a spigot

That said, sand filtration has been shown to significantly reduce the turbidity and chlorine demand of turbid water.

bulletSettling and decanting

This is another method to reduce turbidity in water.

It requires you to let the water sit for 2 to 24 hours so that the particulates settle to the bottom of the container.

Clean water is then decanted off the top of the second container.


  1. Requires no equipment besides the containers


  1. Requires multiple containers
  2. Requires time for the water to settle
  3. If the containers are opaque, it is difficult to observe the settling process

Studies show that the use of settling and decanting significantly reduces both turbidity and chlorine demand in water.

bulletMoringa flocculation

The moringa tree pod contains a seed.

When crushed, this seed is a natural flocculant.

A flocculant refers to the chemical or substance added to a suspension to accelerate the rate of flocculation.

Flocculation creates larger aggregates which make them easier to separate.

For this method, you should pick and dry the pods before removing the seeds.

Next, shell and crush the seeds using a mortar and pestle.

Add about 2 grams of seeds to 20 liters of water.

Stir for 5 minutes and let the water settle for 24 hours before decanting it off into another container.


  1. The seeds are an effective flocculant


  1. This method is time and labor-intensive
  2. The dosing of moringa varies for different water
  3. Two containers are required
  4. The moringa flavor may be objectionable

Studies have shown that the use of moringa greatly reduces turbidity in water.

However, it also significantly increases the chlorine demand in the water because of the additional organic material.

This method isn’t recommended with chlorine-based disinfectants.

bulletRaket flocculation

In Haiti, a cactus called raket contains a natural flocculant.

For this method, the raket must be picked and cut diagonally to expose the maximum flesh surface area.

Then, the raket is added to the water and stirred briefly.

It must sit in the water for 10 minutes before it’s strained through a cloth.


  1. It’s effective at removing turbidity
  2. It’s widely available in Haiti
  3. It’s easy to prepare


  1. It requires two containers
  2. The three-step procedure of raket preparation, addition, and cloth filtration is complicated for the user

bulletAlum flocculation

This method is common in water treatment plants in the United States and Europe.

Aluminum sulfate is wildly available and it’s sold in naturally occurring mineral blocks of soft white stone.

You may see it called “alum.”

You can use alum as a flocculant in several ways, including crushing it into powder before adding it to water, stirring, and decanting.

Likewise, you can stir the whole stone in water for a few seconds and wait for the solids to settle.


  1. Alum is widely available
  2. Alum has been proven to reduce turbidity
  3. Alum is an inexpensive resource


  1. The necessary dosage of alum varies unpredictably
  2. Alum can alter the pH of treated water
  3. Using too much alum can result in a salty, unpalatable taste

Studies have shown that alum significantly reduces the turbidity in water.

It also significantly reduces the chlorine demand of turbid waters.

Final Thoughts

If you have turbid waters on your land, you may worry about the negative effects it can have on your health and land value.

High turbidity in water is unsightly, and it can impact human and aquatic life, especially if you use the land as a water source.

Use the tips above to help you sort out these issues as soon as possible.

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Erika Gokce Capital

Disclaimer: we are not lawyers, accountants, or financial advisors and the information in this article is for informational purposes only. This article is based on our own research and experience and we do our best to keep it accurate and up-to-date, but it may contain errors. Please be sure to consult a legal or financial professional before making any investment decisions.


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