top water contaminants in american drinking water

Even though the United States has one of the safest drinking water supplies in the world, every year, approximately 7.2 million Americans get sick from waterborne diseases. Human senses cannot always detect the organic and microbial contaminants in American drinking water, and sometimes consumers may ingest these impurities for years before anyone realizes a problem exists.

Water near agricultural areas and industrial plants is especially likely to be contaminated with runoff from chemicals, fertilizers, and pesticides. Over time, drinking this contaminated water can increase the risk of cancer, cause reproductive issues, and impair liver, kidney, and other bodily functions.

Perhaps you rely on well water or a pre-treated municipal supply. Either way, if your house isn’t protected by a home filtration system, your tap water may be hiding dangerous impurities. Here are the top 8 bacteria and other contaminants in American drinking water — some of which may be present in your local water supply.


1. Copper

Small amounts of copper are essential for good health, but high levels are harmful. Ingesting high levels can cause nausea, vomiting, and diarrhea, while even higher doses can damage your liver and kidneys.

Unfortunately, copper may leach into your water supply from a number of sources. A few primary sources include:

  • Lakes and rivers treated with copper compounds to control algae
  • Natural water sources that receive cooling water from power plants
  • Copper pipes leaching into corrosive, acidic water in your home

Some of this contamination is removed by water treatment plants, as the Environmental Protection Agency (EPA) requires that levels of copper in municipal water be less than 1.3 mg per liter. However, they don’t regulate what happens to the water once it leaves the water treatment facility. Your exposure risk increases if you have corrosive copper pipes in your home or use private wells and systems that serve less than 15 residences, which are unregulated by the EPA. These types of well systems are not as uncommon as you might think, delivering drinking water to over 34 million Americans.

Concerned that you may be facing copper contamination? One way to lower the copper level in your home is to start the day by letting water run from your faucets for at least 15 seconds before using or drinking it. However, the best way to reduce copper is to install a whole house water filtration system.


2. Fluoride

Fluoride is often added to municipal drinking water and dental products to prevent cavities, and the low-level addition of fluoride to our water supplies has reduced tooth decay by over 25% in both children and adults. However, high levels are known to harm your health. If the exposure is high enough in adults, it can result in fragile and brittle bones, putting you at risk for breakage.

In 2011, after extensive scientific research, federal health officials recommended the optimal level for fluoride in water at 0.7 parts per million. If you have reason to suspect that your water has inappropriately high fluoride levels, it may help to have professionals test your water for purity and drinkability.


3. Lead

Lead is an element that can seep into groundwater from soil or leach into your drinking water through lead pipes, faucets, and fixtures. Lead is highly toxic and can affect almost every organ and system in your body, but the nervous system is affected most. Long-term exposure can cause anemia, decreased memory, and kidney damage. High-level exposure can severely damage the brain and kidneys and cause death.

In consideration of its extreme hazardousness, the EPA set the maximum contaminant level for lead in drinking water at zero. Even at low exposure levels, lead is a highly toxic metal that can cause severe health repercussions. However, once the water leaves the municipal facility, it is no longer monitored by the EPA. There are no regulations on the pipes that bring water into your home, so it’s important to have your drinking water tested at the slightest suspicion of lead contamination.


4. Legionella

Though found naturally in freshwater lakes and streams, Legionella bacteria can become a significant health concern when they grow and spread in building water systems, earning them a place among the most common contaminants in American drinking water. This bacteria thrives in fixtures such as showerheads, sink faucets, hot water tanks, hot tubs, heaters, decorative fountains, and water features.

Legionella spreads easily through water supplies, even able to travel in droplets tiny enough for humans to accidentally swallow or inhale. This exposure is how people contract Legionnaires’ disease, a severe type of pneumonia caused by Legionella.


5. Nitrate/Nitrite

In low levels, nitrate and nitrite usually go unnoticed. But people who consume food or fluids containing an unusually high level of nitrate or nitrite might experience methemoglobinemia, a decreased ability of the blood to carry oxygen to tissues. Related symptoms include increased heart rate, decreased blood pressure, headache, abdominal cramping, and vomiting.

You can suffer nitrate or nitrite exposure in several ways:

  • By drinking water from wells containing nitrate from sources like animal waste or fertilizer runoff
  • Through water contaminated through the release of nitrate or nitrite at waste disposal sites 
  • By consuming contaminated foods, including celery, lettuce, spinach, fruits, fish, dairy products, and beer

Most of the time, people are not exposed enough to cause adverse health effects. For context, the levels allowed by the Food and Drug Administration (FDA) in bottled water are:

  • 10 mg per liter for nitrate.
  • 1 mg per liter for nitrite.
  • 10 mg per liter total for nitrate and nitrite. 


6. Norovirus

Apart from the inherent dangers of undercooked and raw food, norovirus is the leading cause of foodborne illness in the United States. It is a common root behind food poisoning or so-called winter stomach bugs.

Most often, norovirus outbreaks occur in restaurants. If an infected food worker touches anything with their bare hands before serving — including cutlery, dishware, or the food itself — they can easily spread the virus to diners.

However, norovirus can also make you sick as one of the most prevalent contaminants in American drinking water. Water supplies can contract norovirus in several ways:

  • If a septic tank leaks into a well
  • When water isn’t properly treated, usually with chlorine
  • An infected person contaminates the supply through feces or vomit

If your home uses a localized water supply such as a well system, adding a whole house water filtration system can help provide a final line of defense against the spread of illness-inducing bacteria.


7. Uranium

Uranium is a highly toxic radioactive element that exists naturally in dust in the air. It can be redistributed in the environment, settling onto water, reincorporating into the soil, and even sticking to plant roots. 

For the general public, food and drinking water are the two primary vehicles of uranium exposure. In most of the United States, only low levels of uranium are found in drinking water. However, if you live near uranium mining, processing, and manufacturing facilities, you risk being exposed to dangerously high levels through the local water supply.

The same applies to your food. The higher the uranium concentration in the soil where the food is grown, the more uranium can stick to these vegetables. Root crops such as turnips, parsnips, potatoes, and sweet potatoes contribute the highest levels of uranium in your diet. As much as possible, avoid produce grown in contaminated soil, or be sure to thoroughly wash your fruits and vegetables, taking care not to eat the outside portion of root vegetables.


8. Radium

Radium, a naturally occurring radioactive metal, forms when uranium and thorium break down in the environment. Trace amounts of uranium and thorium are found in most rocks and soil, and these radium-forming minerals can create high concentrations in surrounding water supplies. As a result, radium is usually found in well water, fish, and other aquatic organisms, as well as in plants that absorb the metal through the soil.

Everyone is exposed to low levels of radium in the air, water, and food. But the EPA has established a drinking water limit of a combined 5 picocuries per liter for radium-226 and radium-228. Amounts any higher can cause anemia, cataracts, and an increase in broken teeth and cavities. As such, potential radium contamination should be addressed promptly and decisively.


The Science of Water

Even with the oversight of regulations and municipal water treatment plants, there are many dangerous contaminants in American drinking water. But The Science of Water can help you leave fears of contamination behind with a free water test. We evaluate the results and offer our expert recommendations based on the quality of your water. If the water requires additional filtration, we then consult with you to determine which whole house water filtration system would work best for your home and family needs.

We use Puronics drinking water systems, which provide highly filtered, crystal clear water for drinking and cooking. Our systems are eco-friendly and cost-effective alternatives to the expense and hassle of bottled water. 

At The Science of Water, our company is dedicated to providing peace of mind and pure water, one home at a time. Contact us for your free water test, and let’s get started providing safe, clean water to your family today!



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