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Do You Know What’s in the Chicago Water System? Find Out What Could Be in Your Drinking Water!

Do you know what’s in Chicago water? The reality is that the source of Chicago water, Lake Michigan, is anything but untouched.

And for the 6.6 million people in the Greater Chicago Area who depend on the lake for their drinking water, this isn’t to be taken lightly. After all, clean and healthy water is essential to life.

One possible solution to this problem is purchasing bottled water. But this too comes with too many problems. It’s expensive and creates plastic waste. Plus, it’s hard to say if bottled water is healthier than regular tap water!

So, what do you do?

The first step is figuring out what’s in Chicago water. Figuring this out will help you make an informed decision about what to do to clean up your water.

Keep reading to see what contaminations are in Chicago’s drinking water!


Mercury is a naturally-occurring metal found in the environment in small amounts. However, these minuscule amounts aren’t what drives health concerns. The man-made sources of mercury, including coal, trash, and industrial waste, are the real culprit.

Where It Comes From

The biggest source of mercury contamination in the U.S. is coal-fired power plants. These plants release massive amounts of mercury and other pollutants into the air through smokestacks, which rain down into the waterways later.

Coal-fired power plants also produce literal tons of toxic coal ash every day. Coal ash sludge contains numerous heavy metals and other pollutants, including:

  • Mercury
  • Lead
  • Arsenic
  • Iron
  • Manganese
  • Chromium
  • Boron
  • Selenium
  • Chloride

These toxins end up in waterways and unlined pits where they can seep into groundwater, contaminating Chicago drinking water.

Health Risks

Recent laws have restricted the sources from dumping coal ash into water. However, the mercury that was already in the water has lasting impacts. Even a tiny drop of mercury is highly toxic, and mercury stays in systems for years.

Fish and other aquatic organisms can store and accumulate mercury in their bodies over their entire lifetimes.

A high level of mercury exposure can result in significant health risks for people. These risks include:

  • Developmental disorders
  • Nervous system damage
  • Problems during pregnancy
  • Kidney damage
An image of smoke stacks blasting smoke into the air, which contains toxins that impact Chicago’s drinking water.

Many contaminants, like mercury and chromium-6, occur because of industrial processes.


You may know chromium-6 as the infamous pollutant featured in the film Erin Brockovich. The film portrays the $333 million class-action lawsuit launched against Pacific Gas and Electric Company in 1993 for seriously contaminating the water supply in Hinkley, California. This contamination caused hundreds of cases of serious health problems.

Where It Comes From

Like mercury, chromium-6 is a metallic element that naturally occurs in small amounts in the environment. Also, like mercury, it is produced in larger quantities as a result of industrial processes.

The coal ash that seeps into waterways also carries chromium-6. In Illinois, there are 17 such plants discharging toxic ash or wastewater. Another 23 coal-fired power plants and 65 coal ash dumps are right across the lake in Michigan.

The contaminants carried by the coal ash are harmful to the Chicago drinking water quality.

Health Risks

According to the EPA, chromium-6 is found in more than two-thirds of Americans’ drinking water. It presents major health risks, including liver issues, problems during pregnancy, and stomach and lung cancer.

Chromium-6 is one of the possible forms of chromium that can occur in drinking water. The EPA sets no legal limit for the amount of chromium-6 in drinking water. However, it does set a legal limit of 0.1 mg/L of total chromium in drinking water.


Lead is a naturally occurring element found in the earth’s crust. But it can also be found in all parts of our environment, including Chicago water.

Where It Comes From

Lead is another component of that toxic coal ash that makes its way into our water supply.

On top of that, lead can also leach into water from lead pipes that make up much of Chicago’s water infrastructure. This happens especially when the anti-corrosive coatings are disturbed during construction work.

Health Risks

Lead is found in a number of different things, including pipes, lead-based paint, and contaminated dust. Excessive exposure to lead can cause lead poisoning.

Most areas have banned lead-based paint because of the harmful effects of lead poisoning. But lead can still get into systems, impacting the quality of Chicago’s drinking water.

Lead poisoning can result in heart and kidney disease, brain swelling, damage to the nervous system, and death.

Haloacetic Acids

Haloacetic acids are acidic contaminants that are grouped together. The five contaminants are:

  • Monochloroacetic acid
  • Dichloroacetic acid
  • Trichloroacetic acid
  • Monobromoacetic acid
  • Dibromoacetic acid

Where They Come From

Haloacetic acids form when chlorine and other disinfectants are used to treat drinking water. They are chemical byproducts of the disinfectant. And while disinfecting your water can be a good thing, the chemicals left behind are not.

Depending on where you live, you could have anywhere from one of the contaminants to all of them in your drinking water. The City of Chicago currently has elevated levels of dibromacetic acid, dichloroacetic acid, and trichloroacetic acid.

Health Risks

Each of the haloacetic acids listed carries its own set of risks. These acids can increase the risk of cancer and cause problems during pregnancy.

The haloacetic acids are also genotoxic. They can induce mutations and cause damage to DNA if consumed in high enough quantities.

An image showing storage of chlorine, a disinfectant used to treat drinking water.

Disinfectants, like chlorine, leave byproducts in drinking water that can be harmful to your health.

Nitrate and Nitrite

Nitrate and nitrite are two chemical contaminants that can enter your drinking water. Illinois, along with other states, evaluate the levels of nitrate and nitrite together.

Where They Come From

Higher amounts of nitrate and nitrite in drinking water are caused by a few environmental and man-made factors. It can enter your drinking water through animal waste runoff, fertilizers, and septic tanks.

These chemicals seep into the ground and contaminate the water from there. Areas that have higher levels of nitrate and nitrite will have to install specialized treatments in order to get rid of the toxins.

Health Risks

Consuming too much nitrate in your drinking water can have dire health consequences, especially for babies.

Nitrate affects how blood carries oxygen, and it causes methemoglobinemia, also known as blue baby syndrome. A lack of oxygen causes the skin to turn to a bluish color and can result in severe illness or death.

It also increases the risk of decreased blood pressure, higher heart rate, headaches, stomach cramps, and vomiting.

Radium (-226 and -228)

Radium is a radioactive element that can occur naturally. There are two common forms of radium: radium-226 and radium-228. Depending on where you live, the levels of radium can be reported separately or together. Chicago reports its radium levels together.

Where It Comes From

While radium can occur naturally in groundwater, oil and gas activities will increase the levels. These activities often include hydraulic fracking.

Other man-made sources can also contribute to radium in drinking water. It can come from runoff from mining operations and industrial and medical waste discharge.

Health Risks

Radium in drinking water has alarming health concerns.

High enough doses of radium contribute to bone cancer, kidney damage, and congenital defects.

Furthermore, over time, radium can decay into radon, a gaseous contaminant in the air. Increased exposure to radon in the air has harmful effects on people. Radon is the second leading cause of lung cancer next to smoking cigarettes.

Total Trihalomethanes (TTHMs)

Like haloacetic acids, total trihalomethanes are a group of contaminants. This grouping of four chemicals includes:

  • Chloroform
  • Bromodichloromethane
  • Dibromochloromethane
  • Bromoform

Where They Come From

The chemicals in the total trihalomethanes are also byproducts of chlorine and other disinfectants. While these disinfectants are effective at treating water, the byproduct chemicals can cause issues if not taken care of.

Health Risks

The chemicals in total trihalomethanes carry significant health risks in high enough doses. It can include bladder cancer and liver, kidney, and intestinal tumors.

Exposure to the total trihalomethanes can also result in pregnancy problems, such as

  • Spontaneous miscarriage
  • Cardiovascular defects
  • Neural tube defects
  • Low birth weight.
An image of a glass being filled with drinking water from a tap.

A reverse osmosis water filtration system keeps away harmful contaminants, giving you cleaner and healthier drinking water.

How to Get Cleaner and Healthier Water

With all of these contaminants in your drinking water, how do you get cleaner water? The answer is a reverse osmosis system!

The process of reverse osmosis will force water through a semipermeable membrane where contaminants are rejected and flushed. It gives you cleaner, more delicious water for you and your family!

Are You Ready for Healthier Water?

Try our Zero Multi-Stage RO Countertop water filter! The Zero Countertop reduces typical impurities, including the contaminants in Chicago water!

Do you want to see what healthier water tastes like? Stop by Angel Water or give us a call at 847-382-7800 to see how you can improve your drinking water!

Editor’s Note: This blog was originally published in May 2016 and was updated in May 2020.

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