Your Ultimate Guide to Water Contamination

Ever since moving to my town, I have heard people talk about the tap water contaminants here. I never even thought about drinking water contamination in my old home. But if what I was hearing was true, I needed to do something. I didn’t want anyone in my family getting sick from a tainted water supply. I did research about my local water plant and learned some important information. Now I can rest easier.

What Is Drinking Water Contamination?

To say that water is contaminated means it carries anything other than water molecules. That leaves a lot of things to be categorized as contaminants. Drinking water contaminants may or may not cause health problems.

The US Environmental Protection Agency (EPA) categorizes contaminants in water into four groups.

  • Physical contaminants are usually visible, giving the water a cloudy appearance. They often include sediment from soil erosion. Hard water contains physical contaminants.
  • Biological contaminants, also called microbes or microorganisms, include bacteria, parasites and viruses. The traveler’s tummy you experience while on vacation in some countries is often due to biological contaminants.
  • Chemical contaminants are elements from the periodic table or compounds of them. They can be drugs from humans or animals, metals, salts, toxins, nitrogen or pesticides.
  • Radiological contaminants are unstable atoms that give off radiation. These include uranium, plutonium and cesium. They can occur in the soil naturally or come from industrial runoff.

If all drinking water contamination was visible and had a taste and a smell, then you could easily avoid it. The problem is that you often don’t know you have tap water contaminants until:

  • you become ill
  • a series of birth defects occurs
  • patterns of community illness and death emerge

And then your course of action consists of damage control and provision for future generations.

Are There Acceptable Levels of Drinking Water Contaminants?

The Safe Drinking Water Act

The Safe Drinking Water Act (SDWA) of 1974 was passed to help ensure the safety of America’s drinking water.

Because not all contaminants pose the same health risks, the Safe Drinking Water Act (SDWA) directs the EPA to maintain the Contaminant Candidate List, or CCL. It is a list of known contaminants. 

EPA scientists use this to evaluate contaminants in water.

The EPA is charged with regularly reviewing at least 5 contaminants on the CCL to decide if they still pose enough of a health risk to stay on the list. The CCL is also used to help the EPA set priorities for which contaminants to regulate.

What Contaminants Are the Most Harmful?


One of the main culprits in developed countries is chlorine.

According to a report in the February 2002 issue of Environmental Health Perspectives (EHP), public water systems that use chlorine serve over 86 million homes in the US.

The report explains that while chlorine kills some harmful microorganisms, it creates problems of its own. It reacts with residue from leaves and other organic matter and forms harmful disinfection byproducts (DBPs). One large group of these DBPs contains chemicals called trihalomethanes (THMs). Chloroform is in this group. 


Lead poisoning is an issue for all of us, but it is especially harmful to children. It is a heavy metal that can damage their nervous system and cause seizures. It can also cause anemia and even lead to death. 

We are most familiar with the lead that is found in old paint chips, but it is also present in water pipes manufactured before 1986. It leaches into tap water as it passes through the pipes.


Chromium has been on the most wanted list since 2010 when it was found in high levels in the tap water of 31 of 35 American cities tested.

It leeches into groundwater from industrial runoff and can cause stomach cancer, liver and kidney failure, early onset dementia and skin conditions.


Fluoride is the common tooth decay preventative added to toothpaste. But when it is in drinking water, it can actually cause problems with your teeth and even lead to death.

Check to make sure the levels of fluoride in your tap water are no higher than 0.7mg/liter.

Radioactive substances

The uranium in the runoff from nuclear power plants gets into the groundwater and spreads easily. High uranium levels can cause certain cancers, kidney damage and thyroid cancer.


Arsenic has been a known poison for hundreds of years. It is a heavy metal that causes several types of cancer, heart damage and nervous system damage.

Persistent and mobile compounds

Persistent and mobile compounds (PMOCs) are also a big problem.

According to research presented in the November 2019 issue of Chemosphere, “PMOCs can more easily pass wastewater treatment, environmental removal processes and drinking water treatment, and thus pose risks for drinking water production”.

A 2016 study published in Environmental Science & Technology reported that some PMOCs found in waters used for producing drinking water include:

  • methyl-tertbutylether (MTBE)
  • ethylenediaminetetraacetic acid (EDTA)
  • short-chain perfluoroalkyl acids (PFAAs)
  • tris(2-chloroethyl) phosphate (TCEP)

Does that sound like something you want to drink? Not me.

Where Does Contamination Come From?

Any discussion of drinking water contaminants must make a distinction between poor and wealthy countries. 

Water contaminants in poor countries are usually microorganisms–germs. Dirty water can cause:

  • Cholera
  • Cryptosporidium
  • Gastroenteritis
  • Guinea worm disease
  • Typhoid
  • Dysentery

Research published in the May 2004 issue of Toxicology reports that “poor water quality, sanitation and hygiene account for some 1.7 million deaths a year world-wide…”, and that “all except the latter are easily control[ed] by chlorination of water, but re-contamination of treated water is a huge problem.”

Both wealthy and poor countries can be affected by arsenic, benzene, cadmium, lead and trichloroethylene, as they are “…among the most common contaminants found in ground water near hazardous waste sites.”

The industrial process called fracking, or fracing, is also a source of water contamination. Systematic evidence found in a 2011 study conducted in Pennsylvania and New York found that “…methane contamination of drinking water [is] associated with shale-gas extraction.”

The April 2012 issue of Annual Review of Public Health reports that “a number of chemicals are reaching surface waters through the discharge of sewage treatment plants.”

Research published in Environmental Science & Technology adds that “surface waters are, however, the recipients of effluents of wastewater treatment plants (WWTPs) as well as of runoff from impervious urban surfaces and agricultural land.”

Getting an accurate measure of water contaminants in one municipal area can be challenging because concentrations vary by location. In the case of chlorine, the concentration of DBPs increases the further from the water treatment plant you go. 

This is because chlorine continues to react with residues the longer it is in the water. So if your home is 17 miles away from the water treatment plant, you will have more water contamination than someone who lives only 3 miles away from it.

Is Hard Water the Same as Contaminated Water?

Many people talk about “hard water”. What does that mean, and should you be worried about it?

Hard water is water that has high levels of minerals like calcium and magnesium. While these minerals are not likely to make you sick like DBPs can, they do have some pesky side effects:

  • shortening the life of hot water heaters, dishwashers and washing machines
  • increasing water-heater-related energy costs
  • destroying fixtures and faucets
  • building up hard-to-clean scale and stains on bathroom and kitchen
  • clogging plumbing over time
  • creating cloudy water
  • leaving rings around the toilet bowl, bathtub and drains
  • drying out your hair and skin
  • spotting your dishes
  • discoloring your laundry
  • requiring harsh cleaning products

Hard water problems are treated with water softening systems. These systems remove mineral deposits but not water contaminants.

Who Is Most at Risk from Tap Water Contaminants?

Anyone who drinks water contaminated w/DBPs risks long-term health problems, but the most vulnerable include:

  • children
  • elderly people
  • people with immune disorders
  • pregnant women

Research published in the February 2002 issue of Environmental Health Perpectives found that there has been a link between contaminants in water and  adverse pregnancy outcomes for women who drink public water during pregnancy.

What Should You Do If You Suspect Your Water Is Contaminated?

So what can you do? Call your local water company for answers. If you don’t know where to start, try by searching the Water Quality Association’s international water treatment provider search feature. Here you can find out who supplies your drinking water and how to contact them.

The US Environmental Protection Agency maintains a ground water and drinking water website where you can learn about your local drinking water and the regulations in place to protect you. But don’t leave your health outcomes to a governmental agency. Take measures to filter your water to the best of your ability and budget. Better safe than sorry.

Depending on where you live, you can have the water in your home analyzed for free. There is also a variety of home water testing kits available for purchase.

The January 2002 issue of Harvard’s Journal of Young Investigators reports that “…more than 200 million people in the United States consume disinfected drinking water.” 

The researchers say that “an important step towards protection is becoming informed. Read your water provider’s consumer confidence report, and familiarize yourself with the health effects of known or likely contaminants in your area.”

They advise that DBP hazards can be minimized by drinking bottled water or by using a personal water filter.

Call your local water company to find out if they have completed:

  • a source water assessment
  • a sanitation survey
  • review of DBPs

Also ask if chlorine is used to treat your drinking water and how. The US Geological Society (USGS)advises you to ask to read their “drinking water quality report/consumer confidence report that water suppliers now send out by July 1 of each year.”

How Can You Protect Your Family?

While your consumption of DBPs can be lowered by drinking bottled water, you may still be exposed to arsenic, chromium and other contaminants. Your best course of action is to filter your tap water. 

There is a myriad of home water treatment systems on the market. The water purification system you choose for your home will most likely involve distillation, deionization, carbon filtration or a combination.


Systems that make use of distillation create a vapor from the water, leaving the heavy metals and other toxins in the filter.


Purification by deionization involves two tanks. The tanks contain positively-charged hydrogen and negatively charged hydroxyl to attract and retain the harmful toxic ions as pure water passes through.

Carbon filtration

Carbon has been used in healthcare settings as well as air and water filters. Carbon naturally absorbs toxins and lets clean water pass through your tap.

Final Thoughts

The bad news is that you have probably been exposed to water contamination in one form or another. The good news is that by arming yourself with knowledge, you can protect yourself and your family.

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