Water Contaminants | 4 Types of Water Contaminants

Water is the most crucial thing in our lives. Without water, we would not be able to survive. Water keeps us cool, quenches our thirst, and is a significant ingredient in most foods we eat.

We can’t survive without water, but what do we do when our water supply is not healthy? Yes, your water supply can quickly get dirty from many things and lead to water pollution.

Let’s circle back to secondary school; we all know water pollution is dangerous, but why should we make an effort to solve it? Well, we will get extremely sick if we don’t combat water pollution. Water pollution is one of the most common causes of stomach diseases; drinking dirty or contaminated water can trigger mild stomach problems and lead to death.

Water Contaminants

And that’s not all; dirty water is a hot spot for bacteria, viruses, and water-borne diseases. These diseases aren’t only specific to humans; animals can get them too, so dirty water damages our environment and the animals.

Most houses have a pre-installed water filter that cleans the water from the primary source and supplies it to our houses. However, not many people know that these water filters may not be enough to clean the water effectively; some germs, bacteria, and viruses can pass through standard filters, so you always need a unique water treatment system.

Mostly, countertop water filter systems with Reverse Osmosis Membranes or UV light are effective enough to combat all kinds of microorganisms. Still, it’s always best to know what you’re up against. Your water may contain many bacteria, viruses, and even chemicals in trace amounts.

If you want to make the world a better place and improve the water quality in your home, you must know all about water contaminants and how they work. Let’s look into water contaminants and water pollution in detail:

Types of Water Contaminants

Various water contaminants, including bacteria, viruses, chemicals, dirt, debris, and even household garbage, could pollute your water.

We can categorize most water contaminants into four broad types, physical, chemical, biological, and radiological. Let’s take a look.

Physical Contaminants

Physical Contaminants

The most generic and apparent type of water contaminant is a physical contaminant. Physical contaminants only affect the physical properties of water, so a physical contaminant is one that we can quickly detect on sight.

Allow me to explain; when you’re drinking something, and a bug falls into your glass, you can see it and remove it. The bug is a type of physical contaminant since it only drops inside your drink and is visible to you from afar.

A water’s physical contaminants are similar; fallen leaves, branches, dust, floating garbage, soil, and various materials that fall/float/swim in the water are physical contaminants.

Physical contaminants may not thoroughly blend in with water, so we can easily remove them through some form of filtration. Additionally, physical contaminants affect the water quality but only to a small extent, so when we use a filter to remove them, we can come closer to the lost water quality.

We can easily remove physical contaminants using the simplest sediment filter since we only need to separate the physical contaminant from the layer of water.

Chemical Contaminants

Chemical contaminants are far more dangerous than physical ones because they can mix with the water and affect its quality to a greater extent. Chemical contaminants are elements or compounds that can dissolve into the water and significantly affect its taste.

Let us understand this through a simple example; if you were to mix blue ink inside a glass of water, the whole glass of water would turn blue. This is because the blue ink mixes with the water, forcing it to change from its transparent and tasty version into a bluish, contaminated one.

You won’t be able to get the transparent water back even if you try to filter the blue ink water through a sieve, and you won’t drink it because you’ll know it will be dirty even after filtering. This is the effect you get when a chemical contaminant mixes in with the water.

Chemical contaminants are dangerous because they may interact with water or other chemicals to produce toxins or harmful chemicals. When animals or we drink water contaminated by chemicals, we can get severely sick.

Chemical contaminants can be deadly, so we need to filter them. However, generic water sediment filters that separate physical contaminants from water are not enough to separate chemical contaminants. We’ll need more robust filters designed to extract and remove chemicals from the water.

Biological Contaminants

Biological Contaminants

Bacteria, viruses, and germs are all contaminants we can’t see but know are in our water. These contaminants are neither physical contaminants nor chemical but are biological.

Some people might also call biological contaminants microbial/microbiological or microbes.

Biological contaminants are living organisms in the water. Biological contaminants are much scarier and more dangerous than chemical contaminants because they can reproduce and quickly repopulate and contaminate the water.

Biological contaminants are also the leading cause of many water-borne diseases, including typhoid, dysentery, cholera, hepatitis A, and many more severe infections. Water-borne diseases can quickly result in death if untreated, so it is crucial to filter and treat water.

To treat and remove biological contaminants from water, you’ll need a filter that can attack and kill microbes.

Radiological Contaminants

The deadliest type of contaminants, radiological contaminants, contain unstable chemical elements.

Let’s take a short trip down the unpleasant memory lane of chemistry. We learned that some elements do not have stable quantities of protons and neutrons; some elements have too many or too few protons and neutrons and are highly unstable.

The atoms (small particles within a molecule) cannot handle the instability, so they will influence the behavior of these elements by emitting ionizing radiation. Ionizing radiation is highly toxic and can cause lasting damage to our bodies. This radiation can cause cancer.

That’s not the only concern with radiological contaminants; these pollutants can also affect and change our DNA, so a person sick with radiation may have trouble having kids or could have kids with birth defects.

Removing radiological contaminants is extremely tough and requires more than filtration; you’ll need a unique ion exchange filter.

Types of Water Pollution

When various contaminants reside in your water, they can cause water pollution. Water pollution happens when the number/concentration of contaminants gets to an uncontrollable level.

Since there are various types of pollutants, there are also different types of water pollution. Depending on the cause and the type of contaminants, your water could have the following pollution:

Chemical Pollution

Chemical Pollution

As you can tell from the name, when chemicals pollute your water, they lead to chemical pollution. Industrial solvents, chemicals, heavy metals, and certain toxins can lead to chemical pollution.

Certain pesticides or insecticides which run down from the fields to the closest water source can also cause chemical pollution.

Groundwater Pollution

Groundwater pollution happens when man-made products seep and leak into the nearest water source.

You’ll notice that many dirty water bodies (lakes, rivers, or even small ponds) close to any industrial area, chemical factory, or recently constructed buildings or roads.

This is because we often leave contaminants lying on the ground when we use certain chemicals, such as gasoline or petroleum, cement, and other road salts.

These contaminants can move through soil erosion (when water or wind moves the soil from one place to another) and eventually settle in the water, polluting it.

Microbiological Pollution

As the name suggests, when microorganisms like bacteria, viruses, or protozoa reside and populate in a water body, they can cause microbiological pollution.

Everything around us contains microorganisms; there are microorganisms on your work desk, in your bed, on your clothes, in your sinks, and of course, your water supply.

It is not possible to eliminate all microorganisms. Additionally, some microorganisms present in water don’t come from a dirty source; they are there since birth.

Not all microorganisms in the water are dangerous, but most of them can trigger stomach problems in us. For example, E. coli is a bacteria that can trigger an infection that can be painful and uncomfortable to treat. It is best to treat and remove microorganisms because they might not be safe for us.

Nutrient Pollution

Nutrient Pollution

You know the phrase, excess of everything is bad, right? Well, that just became true for water.

Water naturally contains some nutritional elements which are not always harmful. However, the concentration of these can affect the quality of water and disrupt the functions of our bodies.

If the nutrient concentration in the water exceeds the average concentration due to some materials, it can lead to nutrient pollution. The most common cause of nutrient pollution is fertilizers; fertilizers contain many minerals that can seep and pollute your water source.

Oxygen-Depletion Pollution

Oxygen depletion pollution is when the number of oxygen molecules in water decreases; this happens when the number of microorganisms increases because they feed on oxygen.

Although it doesn’t sound too dangerous, it can be. There are two major types of microorganisms, anaerobic and aerobic microorganisms. Aerobic microorganisms can grow and even use oxygen, while anaerobic microorganisms cannot.

In a way, oxygen-depletion pollution results directly from microbiological pollution (if the microbiological pollution happens because of excess aerobic microorganisms).

Aerobic microorganisms consume oxygen and decrease its level in the water, creating an environment where anaerobic microorganisms can grow.

The presence of anaerobic microorganisms is dangerous because they can cause severe infections and diseases in animals and humans.

Surface Water Pollution

Surface water pollution is quite similar to groundwater pollution; in surface water pollution, various contaminants run down from the earth’s surface onto water bodies like rivers and lakes.

Typically, surface water pollution occurs above the ground; various pollutants from the ground can dissolve into the water, dirtying it.

Transboundary Pollution

Did you ever wonder why one country gets upset or mad when its neighbor country builds a significant industry or something similar close to its water? Perhaps you wondered why the United Nations speaks up against the polluted waters of multiple nations.

Why would a different country care? There’s no way that pollution can transfer, right? Turns out it can. Transboundary pollution is when polluted water from one country contaminates a water body in another country by flowing into it. Transboundary pollution is also when one water body pollutes the other by mixing.

For example, when a river becomes polluted, it can pollute the primary source (ocean) when it flows back into it.

Transboundary pollution can happen from any medium. For example, when acidic rain travels from one polluted water source to a clean water source, the rain will contaminate the clean source.

Another example is an accidental oil spill that flows toward the cleaner water source.

Point Source Pollution

You know when something contaminants your water, and you can tell what caused it? This is point source pollution, a type of water pollution in which you can identify the primary source of pollution.

A point source water can be a corroded pipe leaking its eroded chemicals into the water source or the main tube through which factories and industries release their chemical wastes into the water.

Non-Point Source Pollution

Non-point source water pollution is when the water pollution is vast to an extent where you can’t figure out or pinpoint a single source. Non-point source pollution may also be a cause of various sources of pollution.

For example, when a water body near a forest and an industrial area becomes polluted, it is difficult to guess whether the pollution came from the industrial area, the runoff of certain minerals and nutrients from soil erosion in the forest, or both.

Suspended Matter

Typically, finer particles of anything may dissolve and blend with water, but the most matter with bigger insoluble particles cannot do the same. When bigger and insoluble particles come in contact with water bodies, they do not dissolve; instead, these particles hang in a layer.

Eventually, the layer of particles begins to settle down, creating a thick layer at the bottom of the water. This is suspended matter pollution.

Oil Spillages

Oil Spillage in water

Accidental or purposeful oil spills can cause water pollution. Large-scale oil spillage water pollution is a little difficult to treat because oil and water do not mix well; instead, the spilled oil creates awkward layers of dirty and contaminated water and oil.

Most oil spills are accidental when a tanker transporting oil topples and leaks into the water. However, certain cases exist where industries and factories purposefully spill their oil into the water as waste.

Thermal Pollution

The temperature of a water body is critical to the growth of flora and fauna surrounding it. Every organism has a particular environment where it can grow; sudden or drastic changes like temperature changes can severely impact its health.

If something disrupts the temperature of the water, it can trigger an unhealthy environment which may invite harmful microorganisms toward it; this is thermal pollution.

In thermal pollution, additives from specific sources like industrial waste, nuclear power plants, and chemical spills can change and heat the temperature of the water.

EPA Drinking Water Regulations

Water Contaminants | 4 Types of Water Contaminants

The United States’ Environmental Protection Agency (EPA) aims to protect the U.S. and its environment from harm. The EPA recognizes the various contaminants which pollute water and realizes not all of them can be eliminated.

So, the EPA sets certain limits to how much of a contaminant within a water body is acceptable. If the quantity of water contaminants exceeds the legal limit, the EPA can take strict action.

We will look at the EPA water regulations according to the types of contaminants; primary, secondary, and emerging concerns. The regulations for each differ.

●    Primary Regulations

Primary drinking regulations are primary standards that the EPA legally enforces. These primary standards regulations include specific standards which water companies must follow. These regulations also include treatment standards for water filtration and purification.

●    Secondary Regulations

While water companies must follow primary regulations, they don’t have to do the same for secondary water regulations.

Secondary water regulations are not as rigid or enforceable as primary water regulations; instead, secondary water regulations exist as guidelines for us to follow.

Regulations for Contaminants of Emerging Concern

Specific contaminants are either not as threatening or are just capturing the EPA’s attention. While the EPA is not yet enforcing any regulations on these contaminants, it keeps them in sight and brings forth some regulations so water companies can be careful.

These contaminants, which are not yet a threat significant enough to be included in primary or secondary regulations but may be severe enough in some areas, are contaminants of emerging concerns.

●  Primary Contaminants

What primary contaminants frequently pollute the water, and what are the EPA’s regulations about them? We’ll find out.

We can divide primary water contaminants into four common types; microorganisms, disinfectants, inorganic, and organic.  


You’ll frequently find these organisms in your water; here are some regulations about them:

1.  Coliform Bacteria
Water Contaminants | 4 Types of Water Contaminants

Coliform is a type of bacteria naturally present in the environment; we can find Coliform bacteria anywhere. However, the most common forms of coliform bacteria come from fecal waste.

Coliform bacteria like E. coli can frequently pollute water, so they are on the high watchlist of the EPA. A standard demands that there be 0 MCLG (the Maximum Contaminant Level Goal measured in milligrams per liter) of coliform bacteria in the water.

2.  Cryptosporidium

Cryptosporidium can cause severe gastrointestinal illness with symptoms like cramps or diarrhea. Cryptosporidium comes from fecal matter and can pollute water.

The EPA regulates there be 0 MCLG of cryptosporidium in the water.

3.  Giardia

Quite similar to Cryptosporidium, Giardia can trigger gastrointestinal infections and similar symptoms. It also comes from human and animal waste.

There should be 0 MCLG Giardia in your water.

4.  Legionella
Water Contaminants | 4 Types of Water Contaminants

Legionella is a microorganism found naturally in water. Legionella can cause Legionnaires disease, a severe lung infection with pneumonia-type symptoms.

Water bodies must have 0 MCLG Legionella.

5.  Viruses / Bacteria

Other viruses and bacteria which can trigger severe symptoms like vomiting, diarrhea, stomach ache, nausea, and cramp must be 0 MCLG.


We use disinfectants to clean our water, but excessively using disinfectants can pollute our water.

1.  Chlorine

Chlorine can cause eye irritation and stomach problems. The EPA requires the Maximum Contaminant Level Goal for Chlorine not to exceed 4 milligrams per liter of water.

2.  Chloramine

Chloramine is a common disinfectant to control microbe growth in our water; we must maintain no more than 4 milligrams of Chloramine per liter.

C. Inorganic Primary Contaminants

Inorganic chemicals can ruin the quality of water and trigger health problems.

1.  Ammonia

A toxic compound derived from chemical fertilizers and pesticides, ammonia can cause damage to the kidneys and intestines.

There isn’t a set regulation for ammonia; however, most states must not have more than 0.25-0.30 mg/l.

2.  Arsenic

Runoff from electronic devices, glass products, specific industries, and natural deposits can result in a mixture of Arsenic in the water. Arsenic is a highly toxic inorganic chemical that can cause skin damage and even increase the likelihood of cancer.

There must be 0 milligrams of Arsenic per liter of water

3.  Barium

Barium can seep into soil and water from industrial and metal discharge. Barium can increase blood pressure and trigger other health problems.

EPA regulation for Barium is 2 MCLG.

4.  Cadmium

Cadmium can cause kidney damage. This chemical comes from batteries, corroded pipes, and runoff from metal deposits. EPA regulates 0.005 MCLG for Cadmium.

5.  Chromium

Chromium can trigger allergic reactions and dermatitis, so it must not be more than 0.1 milli per liter of water. Chromium comes from natural sources and steel mills.

6.  Copper

Corrosion of pipes and runoff from natural deposits can pollute water with Copper. Copper can cause gastrointestinal problems and liver/kidney damage with prolonged exposure.

EPA regulations ask for a standard of 1.3 MCLG for Copper.

7.  Fluoride

Certain fertilizers and additives contain Fluoride, which can cause bone and joint pain. You must not have more than 4.0 MCLG Fluoride.

8.  Lead

One of the most toxic basic chemicals is lead, which comes from natural sources, plumbing, and pipes. The EPA regulates having 0 MCLG lead in water.

9.  Mercury

Mercury comes from landfills, industrial spills, and natural sources. It can cause kidney damage, so the EPA requires not more than 0.002 MCLG Mercury.

10. Nitrates/Nitrites

Fertilizers may contain nitrates/nitrites, which can pollute the water. Both can cause shortness of breath and other respiratory problems. EPA regulates not having more than 10 MCLG Nitrate and 1 MCLG Nitrite in the water.

11. Perchlorate

High quantities of perchlorate can disrupt the functioning of the thyroid gland, so the EPA requires a set limit of 18 micrograms per liter.

12. Pesticides

Most pesticides do not have set limits since their derivatives have limits themselves.

13. Polycyclic Aromatic Hydrocarbon (PAH)

PAH can cause severe skin infections and even trigger cancers. The EPA regulation for Polycyclic Aromatic Hydrocarbon is 0.2 ppb per liter.

14. Selenium and Uranium

Selenium can cause hair and fingernail loss and disrupt blood circulation in the body. EPA regulation for Selenium is 0.05 MCLG.

Uranium is highly toxic and can increase the risk of cancer. MCLG for Uranium is 0.

15. Silver

Silver can cause liver and kidney damage, eye and skin irritation, and respiratory problems. The EPA requests to keep the limit of silver at 0.05 milligrams per liter.

Organic Chemicals

Certain organic chemicals arise from various sources.

1.  Agricultural Chemical

Agricultural chemicals must not exceed 0-0.1 MCLG.

2.  Industrial Chemical

Industrial chemicals must not exceed 0-0.1 MCLG.

●  Inorganic Secondary Contaminants

The chemicals which the EPA provides some guidelines for are:

1.  Aluminum

The Maximum Contaminant Level (MCL) measured in milligrams per liter for Aluminum is 0.05-0.2.

2.  Calcium / Magnesium

Magnesium and Calcium can harden the water. Since there is no set effect of hardened or softened water, the EPA does not set any guidelines for each.

3.  Iron

EPA requires less than 0.3 milligrams per liter of iron in the water.

4.  Manganese

You must not have more than 0.05-milligram Manganese per liter of water.

5.  Sulfur/sulfate

You mustn’t have more than 250 milligrams of sulfate per liter.

Related Article: Does Reverse Osmosis Remove Boron?

●  Common Emerging Contaminants

These contaminants don’t have a high enough concentration for the EPA to impose regulations, but if the concentration increases, there might be some regulations in the future:

Organic & Inorganic Chemicals

A mixture of inorganic and organic chemicals concerns the EPA:

1.  PFAS (Per and Polyfluoroalkyl Substance)

PFAS are chemicals manufactured for particular purposes. These chemicals are called forever chemicals because they do not disappear.

2.  Personal Care Products

Contaminants derived from Personal care products like OTCs, drugs, sunscreens, lotions, creams, and detergents are on the EPA’s watchlist.

3.  Pharmaceuticals

Medical and pharmaceutical chemicals used in drugs and beauty products might force the EPA to impose regulations in the future.

Oil Spillages

Conclusion | Water Contaminants

There is a lot that can contaminate our water source. We must not treat water contamination lightly since it can trigger severe health problems and disrupt the environment.

There are multiple types of water pollution, each triggered by various water pollutants. The US Environmental Protection Agency keeps an eye on all contaminants, imposing regulations and safety standards for water treatment.

You should install a purifying water treatment system to combat all pollutants.


This is my blog about the ways and solutions that can help you improve your health by taking more value from drinking water. As improving health means a lot to me, I decided to create the Water On Top project with the purpose to reveal the benefits of water, the finest products to take our daily water to another level, and much more great stuff about water that I believe is on top of our nutrition.

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