Common Drinking Water Contaminants in the USA

We list the 10 most common drinking water contaminants which could be hiding in your water. We’ve all heard of Flint, Michigan’s troubles with lead, but I bet you didn’t expect uranium to be on there…

Contamination is defined as rendering something impure, unusable, or harmful in the presence of an unwanted source. Over the last two thousand years civilizations have flourished, but even now as we enter the digital age, we are still unable to guarantee the safety of the most precious of resources: water.  The sources and causes of contamination grow with population of the planet. This means we should always remain alert and inquisitive about where our water is sourced, and the quality of that which comes out of the faucet or shower.

The causes of contamination range from industrial waste, chemicals used in farming, fracking, negligence, to sewage. There are of course many other reasons, with global warming being another factor. As we encroach further into natural habitats to mine and plunder, we put many natural things at risk, one of these being water. Today, we are going to mention some of the most common water contaminants.



The Four Types of Contaminants

The primary water contaminants are physical contaminants which you can see in the physical appearance or other physical properties of water. An example would be soil erosion in the rivers, streams, and lakes. Next are the chemical contaminants which would be elements or compounds found in the water which can be man-made or natural. Examples would be bleach, salt, toxins, pesticides, or nitrogen. Then there are the biological contaminants which are organisms in water or also called microbiological contaminants. These could be parasites, bacteria, or viruses. Finally, there are the radiological contaminants. These are chemical unstable elements that give off radiation.  For example plutonium or uranium.

The Environmental Protection Agency (EPA), is able to identify these contaminants and sets regulatory limits for the amounts of certain contaminants in water provided by public water systems. These standards are required by the Safe Drinking Water Act (SDWA) which ensures that the EPA implements these provisions and protects the public’s health.

water contamination usa


The 10 Most Common Water Contaminants

It’s very easy to forget the fact that your household drinking water probably started life very far from your kitchen faucet. It may have flown down streams, through farmland, and even through sewers at some point. Now, we now for a fact that it has been through the water treatment plant, but how thorough have they been? We also know that water contamination can also happen long after the water leaves the plant and starts making its journey to your home.

Now, the ten most common contaminants may not be in every drink you take or even any, but they are a threat to people all across the United States. Let’s take a look at the most common contaminants below.


  1. Aluminum (Al): Low-level exposure is not thought to be harmful, but long-term intake has been linked to impaired brain function, including Alzheimer’s disease. (Federal Limit 0.05 – 0.2 mg/L)
  2. Arsenic: The chemical element of atomic number 33, is a brittle steel-gray metalloid. Exposure can cause damage to your circulatory system and skin. The federal limit is 0.01 milligrams per liter.
  3. Lead: The chemical element of atomic number 82, is a grayish-blue ductile metal. Exposure can cause brain, kidney, and nervous system damage. Lead is extremely harmful for children. The federal limit is 0.015 milligrams per liter.
  4. Zinc: The chemical element of atomic number 30, is a white metal used for coating steel and iron. Exposure can lead to anemia. The federal limit is 5.0 milligrams per liter.
  5. Barium: The chemical element of atomic number 56, is a white, soft reactive metal of the alkaline earth group. The symptoms of barium poisoning include increased blood pressure, changes in heart rhythm, stomach irritation, and muscle weakness. The federal limit is 2.0 milligrams per liter.
  6. Lithium: The chemical element of atomic number 3, is a silver soft metal that is extremely light. Exposure can cause nausea, vomiting, diarrhea, and kidney damages. There is no federal limit in your water and occurs naturally.
  7. Nitrate: A mixture of nitric and sulfuric acids, it is a salt or ester of nitric acid. Exposure can cause brain damage as well as death and affects infants younger than 6 month. The federal limit is 10 milligrams per liter.
  8. Uranium: The chemical element of atomic number 92, is a dense, gray radioactive metal substance that occurs naturally. Exposure can cause kidney disease in high levels. The federal limit 0.03 milligrams per liter.
  9. Silver: The chemical element of atomic number 47, is a shiny grayish-white metal. Exposure begins to poison humans causing skin discoloration and leads to death. The federal limit is 0.1 milligrams per liter.
  10. Beryllium: The chemical element of atomic number 4, is a hard gray metal. It is the most toxic chemical known and a probable human carcinogen. Exposure can cause mutation and cancer. The federal limit is 0.004 milligrams per liter.


For further information about these drinking water contaminants you can visit these pages by the Environmental Protection Agency, Water Quality Association, and U.S. Government.

We should truly be concerned about contaminates that we are being exposed to. We should be wary about the things that we consume and the effects they have on our bodies. It is worth taking the time to stop and read more about our drinking water and how it is processed before being given to us. This includes the tap water from our sinks as well as bottled water we buy from the store. It is time to start drinking smart and making healthy choices about our water.

Learn more about effective water filters with our guides to water filtration.

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Hi I'm Jamie, teacher and owner/chief contributor at We strive to bring you the most informative water filter reviews in the most intuitive and user friendly way. Besides offering advice on the water filter to suit your needs, we also post topical articles on water pollution and the environment. Stay connected and follow us on, Facebook, Twitter, Google+ and more!

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