While you might be meeting your daily hydration goals, what’s really in your tap water might be quietly impacting your health in more ways than you realize. From chlorine to PFAS and lead, your ‘clear’ glass of water may contain several water contaminants that are slowly building up inside you.

So, how do you protect yourself and your family? You start by knowing what’s in your water and how it can impact your body over time. This guide helps you do just that. We walk you through the 10 common water contaminants found in household water and explain their health effects so that you know exactly what you’re up against.

What are Water Contaminants?

The Safe Drinking Water Act (SDWA) defines contaminants as any physical, chemical, biological, or radioactive substance in water. Simply put, water contaminants are substances that should not be in your drinking water or those that exist beyond ‘safe limits’.

Now, you may be wondering, ‘Who decides these ‘safe limits’?’ It’s the EPA. 

Under the SDWA, the EPA has established protective drinking water standards for more than 90 water contaminants, including lead, total coliforms, and chlorine. You can read more about the EPA limits here. 

Types of Water Contaminants

Knowing the meaning of water contaminants isn’t enough. You also need to understand the different types of contaminants that can enter your glass. The EPA classifies drinking water contaminants into the following categories:

• Physical: As the name suggests, these contaminants affect the appearance of the water. Common examples include soil and sediments.
• Chemical: These are naturally occurring or man-made chemical compounds impacting the quality of your drinking water. Examples of chemical water contaminants include metals, salts, pesticides, and bleach.
• Biological: Microbes like bacteria, protozoa, and parasites found in drinking water fall under this category.
• Radiological: These are elements like uranium and plutonium that can emit ionizing radiation into your drinking water.

Top 10 Water Contaminants Found in Household Water and Their Health Effects

Now, let’s look at the top 10 common water contaminants that may be causing water quality issues:

1. Lead

If your home was built before 1986, there’s a good chance it may have lead pipes or older plumbing that can leach lead into your drinking water. Lead is a toxic metal that often enters water through aging pipes, faucets, and fixtures — sometimes without any visible signs.

According to the EPA, there is no ‘safe level’ of lead in water. This means exposure to even low levels of lead in your drinking water can affect your health. 

Possible Health Issues from Lead in Water:

• For kids: Behavioral and learning problems, developmental delays, anemia, lower IQ, and slowed growth. The CDC recommends public health actions if the level of lead in a child’s bloodstream is 3.5 micrograms per deciliter.
• For pregnant women: Lead can cross the placental barrier, causing reduced growth of the foetus and premature births. It can also be transmitted through breast milk.
• For adults: Cardiovascular effects, increased blood pressure, decreased kidney function, and reproductive problems.

Generally, the health effects of lead can be more severe in kids. As one Reddit user shared, their toddler was diagnosed with dangerously high lead levels that had built up over time and were even leaching from her bones.

She had always thought her child’s behavior issues were just ADHD — until the lead diagnosis showed that much of it may have been linked to lead exposure.

2. Arsenic

Arsenic is a toxic heavy metal commonly found in U.S. groundwater, particularly in private wells. In fact, studies by the USGS have found arsenic in drinking water wells across more than 25 states, potentially exposing about 2.1 million people to high arsenic levels.

Some places, like Minnesota, can have high levels of arsenic mixed in the water. So, if you live in Minneapolis, MN (and get water from a private well), where arsenic levels in drinking water can be high, it’s best to get your water tested by professionals at InHaus Lab.

Possible Health Issues from Arsenic in Water:

According to the WHO, the provisional limit for arsenic in drinking water is 10 µg/L. But even then, arsenic can lead to health issues because arsenic is a known carcinogen, as per the International Agency for Research on Cancer (IARC).

• Acute effects: Symptoms of acute arsenic poisoning can include vomiting, abdominal pain, and diarrhea. These may be followed by tingling in the legs and hands, muscle cramping, and even death.
• Long-term effects: Arsenic water may be harming your skin, causing pigmentation, lesions, and hardening. Long-term exposure can also lead to skin, lung, and bladder cancers.

3. Coliforms

While coliforms don’t always cause health effects, their presence suggests that other water contaminants may be present, according to the EPA. Typically, this means the presence of other microbes and parasites.  

E. Coli, Cryptosporidium, and Giardia Lamblia are some common microorganisms found in groundwater. So, if there is E. Coli in the water, it could mean the water has come in contact with sewage. 

Possible Health Issues from Coliforms in Water:

As mentioned earlier, the health risk comes from bacteria or parasites that cause drinking water issues, not coliform per se. Here’s what they can cause:

• E. Coli: Diarrhea, vomiting, and fever
• Cryptosporidium: Gastrointestinal illness with cramping and diarrhea
• Giardia Lambia: Diarrhea, vomiting, and cramps

4. Chlorine and Chloramines

It is not uncommon for municipalities to add chlorine and chloramines (chlorine + ammonia) to water to kill microorganisms and disinfect it. The CDC limit for chlorine levels is 4 mg/L. So you might be wondering how it's a water contaminant if it’s supposed to do the opposite.

Well, it becomes a water contaminant only when it reacts with organic material to form disinfection byproducts (DBPs), such as trihalomethanes (THMs) and haloacetic acids (HAAs), which are carcinogens. 

Possible Health Issues from Chlorine and Chloramines in Water:

Apart from making the water taste bad, excess chlorine and chlorine byproducts can also cause:

• Skin, eye, and nose irritation
• Asthma
• Stomach discomfort
• Bladder cancer
• Reproductive and developmental effects

5. Nitrates and Nitrites

Nitrate is a common chemical found in fertilizers and liquid waste that’s discharged from septic tanks. Moreover, bacteria in soil also convert the natural nitrogen into nitrate. 

Runoff from fertilizers or rain can carry this nitrate from the soil into the groundwater. When this inorganic water contaminant enters your body, it’s converted into nitrite. 

Possible Health Issues from Nitrates and Nitrites in Water:

• Short-term effects: High levels of nitrate water contaminants can make infants seriously ill by reducing oxygen in the blood, causing shortness of breath and bluish skin (Blue Baby syndrome or Methaemoglobinaemia).
• Long-term effects: Long-term exposure to nitrate and nitrite water contaminants may affect the thyroid, spleen, and kidneys, leading to internal bleeding and other health problems. Moreover, the CDC lists them as possible carcinogens.

6. PFAS

If you’ve been reading about health, you must have come across the words ‘forever chemicals’. This is the common name for Per- and Polyfluoroalkyl Substances (PFAS), which are also common water contaminants in the U.S.

Simply put, PFAS are widely used, long-lasting chemicals that are found in everything from non-stick cookware to fire foam. PFAS cause drinking water issues because they break down very slowly and can accumulate in your body over time.

Possible Health Issues from PFAS in Water:

As per the EPA, peer-reviewed scientific studies have shown that exposure to certain amounts of PFAS can lead to:

• Reproductive effects, such as decreased fertility and high blood pressure in pregnant women
• Increased risks for prostate, kidney, bladder, and testicular cancers
• Increased cholesterol levels (risk of obesity)
• Development delays in children, including low birth weight, bone variation, or behavioral changes
• Hormone imbalance

7. VOCs

VOCs, or volatile organic compounds, are chemical compounds that can easily evaporate as gases. Thousands of products, including gasoline, additives, and paints, contain VOCs, so it’s not surprising that some of them end up as water contaminants, causing drinking water issues. 

Possible Health Issues from VOCs in Water:

The health risks associated with VOCs depend on the specific VOC. For instance:

• Benzene can cause anemia and increase risks of cancer
• Trichloroethylene can cause liver problems and cancer
• Chlorbenzene can cause liver and kidney damage

That’s why the EPA has set Maximum Contamination Limits for over 20 VOCs, outlining their potential risks as well.

8. Sediments, Dirt, and Dust

Does your water look murky? Are there tiny particles floating inside? If so, your drinking water may contain sediments, dirt, and dust.

These common water contaminants generally enter your water as rust from iron pipes, sand from soil intrusion, or simple debris from the construction of new pipelines. While most are harmless, some may carry pathogens or chemicals that are dangerous.

Possible Health Issues from Sediments, Dirt, and Dust in Water:

• Digestive issues like stomach discomfort and gastrointestinal problems
• Development issues in children if the sediments include heavy metals

Apart from health issues, these water contaminants can also damage your appliances, costing you frequent repairs and replacements.

9. Fluoride

‘Isn’t fluoride good for tooth health?’ - If this was the first question that came to your mind on reading this, you’re right. Fluoride is effective at preventing cavities, but in excess, it can become a common water contaminant. 

That’s why the EPA has set the fluoride limit at 4 mg/L.

Possible Health Issues from Fluoride in Water:

• Dental fluorosis
• Thyroid issues
• Bone pain and tenderness
• Possible bone fractures

10. Pesticides

Pesticides can wash down household drains and travel through sewer systems to treatment plants, where many remain untreated and end up back in water supplies.

So do all pesticides cause drinking water issues and health effects? The EPA says it depends on how toxic the pesticides are, how much is in the water, and how much you are exposed to daily.

Possible Health Issues from Pesticides in Water:

With hundreds of different pesticide compounds in use — and limited testing on many of them — their long-term health effects remain poorly understood. That said, here are what some studies have found:

• Reduced vision
• Headaches
• Salivation
• Diarrhea
• Nausea
• Vomiting

In extreme cases, exposure to this water contaminant can lead to coma and death as well.

Sources and Health Risks of Common Water Contaminants: A Quick Overview

Here’s a quick overview of the common water contaminants, their sources, and health risks:

Suspect Water Quality Issues? Don’t Wait, Call the Professionals

Now you know that even your seemingly clear glass of water can hide hundreds of water contaminants that can put your and your family’s health at risk. Remember that these risks can increase when these water contaminants go unnoticed for years. 

So, how do you find out if your water is really clean or not? You can call InHaus Lab for a comprehensive and science-backed water quality assessment. Our certified professionals will come in and test your water, providing verifiable results to help you decide the next steps.

Call InHaus Lab, and get a quote in 30 minutes!

Common Drinking Water Contaminants FAQs

1. Is tap water in the U.S. safe to drink?

While tap water in the U.S. is regulated by the EPA, it can still contain harmful contaminants like lead, PFAS, and excess chlorine levels. Aging pipes, industrial runoff, and outdated infrastructure can make your water unsafe to drink. The only way to know whether your tap water is safe is to have it professionally tested.

2. What are the common drinking water contaminants I should be aware of?

Some common drinking water contaminants you should know about include:

• Lead
• Chlorine
• Fluoride
• PFAS
• Arsenic
• VOCs
• Coliforms

3. How can I remove PFAS, or ‘forever chemicals,’ from my drinking water?

The most effective methods of PFAS removal include:

• Activated carbon filters (like high-quality pitcher or under-sink filters)
• Reverse osmosis systems
• Whole-house filtration for severe contamination

It’s best to have a professional come and test your water to help you decide the right next steps.

4. What happens if there is lead in water?

Lead in drinking water can cause serious health problems, especially in children and pregnant women. It can affect brain development, learning ability, and behavior in kids, and increase blood pressure and kidney problems in adults.

There’s no safe level of lead exposure — even small amounts can be harmful over time.

5. How often should I test my water quality?

If you have a private well, the EPA and CDC recommend testing every year. Similarly, if you get water from a local supplier, they are required by the Safe Drinking Water Act to send you information on water quality every year.

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References

• EPA, Types of Drinking Water Contaminants
• EPA, Basic Information About Lead in Drinking Water
• CDC, About Childhood Lead Poisoning Prevention
• WHO, Arsenic
• USGS
• CDC, About Water Disinfection with Chlorine and Chloramine 
• EPA, Our Current Understanding of Human Health and Environmental Risks of PFAS
• EPA, Drinking Water and Pesticides
• NLM
• EPA, Revised Total Coliform Rule
• EPA, National Primary Drinking Water Regulations