It may sound dramatic when we say that the water you drink can be detrimental to your health, but take a look at this list we’ve compiled of the most prominent contaminants that are lurking in your drinking water. 

Regardless of whether you’re drinking tap water or well water, federal regulations for these contaminants far exceed what researchers and experts deem to be “safe” levels of contamination.

Chromium-6, also referred to as chromium (hexavalent), is a naturally occurring heavy metal, but can be formed as a by-product of industrial manufacturing. It enters groundwater due to these industries’ pollution and from natural gas compression stations that use it as an anti-corrosion agent in cooling water. 

The substance is toxic at very low levels. The World Health Organization (WHO) considers it a Group 1 carcinogen as it is known to cause cancer in extremely small concentrations, to the point that California scientists consider Chromium-6 dangerous when it exceeds 0.02 parts per billion (ppb). 

Long-term exposure can result in damage to the liver and reproductive systems, lower the body weight, and delay skeletal development.

Scientists have identified that infants, children, and people taking antacids, as well as people with poorly functioning livers are most vulnerable to chromium-6 exposure.

HAA5, a collection of five haloacetic acids widely considered to be the most prevalent and potentially harmful in tap water, is a disinfectant byproduct of water chlorination that can be found in tap water in all 50 states. When water treatment facilities use chlorine or other disinfectants to treat the water, it can form compounds called disinfection byproducts (DBPs). 

This process is quite common and can potentially affect any water source treated with chlorine-based disinfectants. 98% of America’s public water supplies are disinfected with chlorine, which means 98% of our tap water has the potential to be contaminated with HAA5!

HAA5 has been linked to multiple forms of cancer, as well as harmful to fetal growth and development. Exposure can lead to increased risk of headache, nausea, sore throat, wheezing, shortness of breath, liver damage, and kidney problems. 

Long-term exposure to contaminated drinking water may cause vomiting, diarrhea, and sore throat due to HAA5's potential to burn the tissues of the human body

The EPA allows up to 60 ppb of HAA5 in our tap water, but based on the Environmental Working Group's (EWG) research and other peer-reviewed scientific studies, experts suggest the EPA allows 600x too much HAA5 in tap water. Even worse, HAA5 levels in drinking water systems exceed the EWG guidelines in all 50 states!

Radiation is not only a product of nuclear power plants, reactors, and X-rays, radioactive elements can be found naturally in the environment – in the air we breathe, the food we eat, and in the water we drink. Several radionuclides, including radium, radon, and uranium, have been detected in U.S. drinking water supplies.

According to an EWG analysis, more than 170 million Americans have been drinking water containing radiological elements at potentially dangerous levels. 

Prolonged exposure to high levels of radiation is linked to several types of cancer and other health issues. As these elements break down over time, some emit ionizing radiation that can lead to bone cancer, lung cancer, liver cancer, tumors, leukemia, and other health effects as it damages the DNA in our cells.

On top of that, when pregnant women drink water contaminated with radioactive materials, it can lead to birth defects and other developmental problems.

The EPA established the Radionuclides rule to protect public health against radioactive contaminants in drinking water, but it is important to note that these standards are only guidelines and not guarantees of safety. In fact, the EWG, as well as other health and safety authorities, believe that many radioactive materials can be dangerous to human health even at levels the EPA legally allows.

Plastic is a nearly indestructible material that will never fully decompose. It simply continues to break up into smaller particles over time, eventually producing what we call microplastics - particles less than 5 millimeters in size. 

The size of these particles makes them easily transferable through our groundwater and freshwater sources through runoff, stormwater, and wastewater. 

Plastic particles are breeding grounds for biofilms made of harmful bacteria, viruses, and other contaminants. The microplastics carry these biofilms through the water system right to your home's tap.

As expected, one of the main sources of microplastic is plastic waste. A few other sources of microplastic pollution in our drinking water supplies include:

• personal care products: toothpaste, facial scrubs, and sunscreens that contain microbeads

• synthetic fibers: tiny plastic microfibers can shed from synthetic clothing 

• agricultural products: fertilizers and mulch may contain plastic particles

The WHO published a report after combining data from 50 independent water research studies to better understand the current levels of microplastics in freshwater, drinking water, and wastewater with results showing widespread microplastic contamination.

Scientists are still studying the effects of microplastics on human health and are increasingly discovering adverse health impacts – microplastics were recently found in human lungs, breast milk, and even placental tissue. 

As microplastics break down, the particles become small enough to pass through areas where it had been thought they could not reach, such as the blood-brain barrier, which is a network of tissues that protects the brain from toxins and pathogens.

Arsenic is a naturally occurring mineral found in drinking water in all 50 states that can also be produced through mining, farming, and other industrial processes. 

Both the EPA and the WHO established arsenic as a “known human carcinogen,” based on evidence that suggests arsenic exposure is linked with the risk of bladder, lung, skin, liver, kidney, and prostate cancers. Arsenic poisoning can also lead to skin lesions, harm to kidneys and other internal organs, and cardiovascular disease. 

Data from the EWG shows 109 million Americans were exposed to arsenic-tainted drinking water between 2016 and 2020, meaning nearly 1 out of 3 Americans could be drinking water contaminated with arsenic. Furthermore, these estimates don’t include people who drink water from private wells that might have unsafe levels of arsenic.

The official EPA maximum contaminant level (MCL) for arsenic contamination is 10 ppb, but the EWG suggests that no more than 0.004 ppb of arsenic should be allowed in water to protect the public from cancer risk and reduce exposure.

It’s ironic that a chemical used to disinfect and treat our water – chlorine – may also result in the formation of a hazardous substance: chloroform. 

Chloroform – a DBP of chlorine –  is found in 46 states and affects upwards of 220 million people. Approximately 98% of tap water is treated with chlorine and the amount used to disinfect water supplies constantly changes depending on emerging contaminants, aging infrastructure, and natural disasters. As a result, an increase in chlorine use – or any other disinfectant – can lead to increased chloroform concentration. 

But water treatment isn't the only cause of chloroform contamination – it can also be found at paper mills, hazardous waste sites, and landfills where it can sneak into water supplies if mismanaged by these sites.

Chloroform can easily enter your body through air, food, and drinking water. You can also be exposed through skin contact, so bathing or showering in water containing chloroform may allow the chemical to enter your body. A hot shower can lead to chloroform inhalation if the heat causes it to evaporate.

Once inside your body, chloroform doesn't stay localized. It's carried by your blood to your entire body, including areas like your fat, liver, and kidneys.

Short-term chloroform exposure may cause central nervous system depression, while prolonged exposure may cause more serious health issues including hepatitis, jaundice, depression, brain damage, and an increase in cancer, particularly in the kidneys and liver.

According to the Centers for Disease Control and Prevention (CDC), a study showed that people who consumed chlorinated water showed a link to the increased risk of cancer in the colon and urinary bladder. 

Furthermore, the Department of Health and Human Services (DHHS), the International Agency for Research on Cancer (IARC), and the EPA have all determined that chloroform could be considered a carcinogen, meaning it has the potential to cause cancer in humans.

Nitrates are one of the most common contaminants found in drinking water due to runoff, wastewater, landfills, animal feedlots, septic systems, and urban drainage. These compounds are virtually undetectable as they are tasteless, odorless, and completely invisible to the naked eye.

While water with a high nitrate concentration is most common in well water (largely due to its close proximity to soils rich in nitrates), analysis by the EWG shows that nitrates are an issue for water systems in both rural and urban areas. EWG’s Tap Water Database states that 237 million people drank water from a public water system that shows detectable traces of nitrate in 2019.

The biggest concern regarding nitrate contamination in drinking water is that it poses a high risk to infants and children and can lead to a condition called methemoglobinemia, also known as “blue baby syndrome.” It is a potentially life-threatening condition that reduces the ability of red blood cells to carry oxygen and in serious cases can result in long-term issues including memory loss, attention deficits, and learning disabilities. Infants exposed to high nitrate levels in the womb may show signs of delayed physical and cognitive development. 

In a peer-reviewed study by the EWG, it was determined that nitrate exposure was possibly “responsible for as many as 2,939 cases of very low birth weight; 1,725 cases of very preterm birth; and 41 cases of neural tube defects.”

Nitrate exposure also poses a great health risk to adults – excess nitrates in adults can lead to nausea, headache, rapid heartbeat, and gastrointestinal disorders. 

The EPA has set an enforceable  MCL at 10 parts per million (ppm), however, epidemiological research suggests that the current nitrate limit does not adequately protect public health. As a result, the EWG Health Guideline suggests the MCL for nitrates should be set at 0.14 ppm to protect against cancer and harm to fetal growth and development.

Historically, trichloroethylene (TCE) was used in a wide range of industrial and commercial applications, including as a dry-cleaning solvent, an anesthetic, and in carpet cleaners, spot removers, office products, and many other home-use products. Currently, TCE is used in vapor degreasing and as an intermediate in the production of hydrofluorocarbon refrigerants and other chemicals.

According to the Agency for Toxic Substances and Disease Registry, between 4.5% and 18% of the drinking water tested by the EPA have been contaminated by TCE. Furthermore, the EWG found that common groundwater pollutant affects community water systems serving at least 19 million people in the U.S. 

With its uses as an industrial solvent, it’s safe to say that TCE is not something that you want in your drinking water. According to the EWG, TCE poses health risks through ingestion, inhalation, and skin absorption and can lead to adverse health effects like:

• damages to the immune system

• harm to the developing fetus

• increased risk of cancer 

• linked to developmental and reproductive harm

• various immune and neurological defects

• higher risk of developing Parkinson’s Disease

Both the International Agency for Research on Cancer and the Department of Health and Human Services have classified TCE as a human carcinogen, most commonly linked to kidney and liver cancer and non-Hodgkin lymphoma.

The EPA established a MCL of 5 ppb for TCE in drinking water, but the Minnesota Department of Health and the EWG agree that 0.4 ppb would be a better measure to protect the immune system.  

As it stands, the EPA proposed a plan to ban all uses of TCE saying it presents an unreasonable risk to human health. If the rule is finalized, it would ban most uses of the chemical in industrial processes and opt for safer alternatives to TCE.

Lead is a metal that can be found in all parts of our environment, but most of our exposure to lead can be attributed to proximity to lead-based paint and drinking water that is sourced from a system with lead-based pipes. 

Historically, lead was used in water lines in hundreds of cities, and as these pipes corrode, lead leaches into our water supply.

While lead-based pipes are no longer being built, lead service lines are typically the most significant source of lead in the water and in 2016, the American Water Works Association estimated that 15 to 22 million Americans are drinking water from a system with lead-based pipes. 

In an effort to minimize and control lead contamination in water, the EPA established the Lead and Copper Rule (LCR)under the authority of the Safe Drinking Water Act. The LCR replaced the existing MCL with treatment techniques that are implemented if lead concentrations were to exceed 15 ppb. However, the California Office of Health Hazard established a public health goal for lead at 0.2 ppb – that’s 75x smaller than the EPA’s action level – to protect against harm to children’s brains and nervous systems.
This neurotoxin can cause major damage to your health, even in trace amounts. 

In adults, lead exposure can result in severe brain and kidney damage, increase blood pressure and hypertension, and reproductive issues. 

While lead poisoning affects everyone, pregnant women and children are at the highest risk. During pregnancy, the fetus could be exposed to lead that crossed the placental barrier, resulting in severe risks to both the mother and the fetus and lead to reduced growth of the fetus and premature birth. 

Children are especially vulnerable to lead poisoning due to their still-developing nervous system and their bodies are able to absorb metals at a higher rate. At low levels of exposure, lead can impair mental development and physical growth, alongside behavioral problems. High levels of lead exposure can result in anemia, muscle weakness, and brain damage.     

Lead has been recognized as a potential carcinogen by the Department of Health and Human Services, the EPA, and the International Agency for Research on Cancer.

It may come as no surprise that perfluoroalkyl and poly-fluoroalkyl substances (PFAS) top the list for leading contaminants in your water. PFAS do not break down over time, hence the nickname “forever chemicals.” In fact, these chemicals can stay and accumulate in the body and environment for years.

PFAS pollution is often linked to industrial waste, landfills, airports, and military bases where the chemicals are commonly used. Scientists have found upwards of 40,000 potential sources of PFAS that could contribute to our water supplies. Analysis from the EWG found that 43 million Americans (and up to 200 million Americans, which is more than half of the population) are now served water that exceeds the latest EPA recommendations for PFAS levels. In fact, studies show more than 98% of the U.S. population already have detectable PFAS concentrations in their blood. 

Multiple studies, including the largest epidemiological study ever in human history, found links between PFAS and many alarming health risks: 

• thyroid disease

• high cholesterol

• cardiovascular issues

• ulcerative colitis (IBD)

• liver damage and liver tumors

• kidney and testicular cancer

• weakened immune system

• irritable bowel syndrome (IBS)

• hormone imbalance

• DNA damage

• increased risk and severity of COVID 19 symptoms

PFAS exposure is particularly harmful for pregnant women, infants, and children, with additional health effects ranging from skeletal variations (congenital disabilities), low birth weight, decreased response to vaccines to increased likelihood of miscarriage, high blood pressure, preeclampsia during pregnancy. Additionally, babies exposed prenatally can have a higher risk of experiencing obesity, early-onset puberty, and reduced fertility later in life, alongside other developmental issues.

PFAS accumulate in the body and are harmful at very low levels. A proposal by the EPA suggests that the MCL across all water utilities, should be 4.0 parts per trillion (ppt). Keep in mind, most contaminant levels are regulated in parts per million (ppm).

Cancer-linked PFAS are legally allowed to pollute public drinking water supplies in all 50 states, since testing (and removal) for these chemicals is not required. Experts estimate 200 million Americans drink tap water contaminated with toxic PFAS daily. Given the lack of testing and regulations, it’s safe to say that’s likely a conservative estimate.

Considering the contaminants we’ve just discussed are most likely presently in your water, your best bet for clean and safe drinking water is an adequate filtration system.

It may seem daunting to think of all the toxins hidden in your water, but here's the good news: Clearly Filtered offers a line of premium water filtration systems powered by our proprietary Affinity® Filtration Technology for the absolute best protection from harmful contaminants. Our breakthrough filtered water pitcher targets 365+ contaminants, including all of the aforementioned contaminants, so that you can trust every drop. 

Visit our website to view our lab test results in detail, and then select your system and upgrade to Clearly Filtered.