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To protect drinking water from disease-causing organisms, municipal authorities routinely add disinfectant to public water supplies. Chlorine is by far the most widely used chemical for this purpose.

This important and very necessary process of disinfection has significantly reduced the incidence of waterborne illness by killing disease-carrying microbes. However, unknown to most people, the process also creates other more potent toxins that are extremely difficult to remove. This includes a chemical getting more attention within the scientific community – trihalomethanes. =

The Effects of Water Disinfection on our Bodies

Science is asking new questions about the long-term health effects from drinking, bathing, showering and swimming in chlorinated water.

We have all experienced the outward effects that chlorinated water can have on our bodies. These include:

  • Turning our skin dry, itchy and red.
  • Removing the natural oils covering our hair resulting in a loss of hair shine and flexibility causing dry porous strands.
  • Inhaling the steam and spray while showering where it reduces oxygen transport in our lungs and enters our bloodstream. This has the effect of accelerating aging from free radical damage. Further, it causes the destruction of valuable vitamins needed by our bodies. It also can cause irritation and discomfort to our eyes, nose, and stomach as well as the death of probiotics in and on bodily tissues.

As alluded to above, chlorine itself is not the only worrisome chemical in municipal water. In fact, it is one of the least problematic despite getting most of the attention.

How Chlorine Transforms into Disinfection By-Products

Chlorine can and frequently does react with the many naturally occurring organic and inorganic compounds found in our water supplies.

This results in the creation of even more harmful compounds such as Trihalomethanes (THMs), Haloacetic Acids (HAAs) and Mutagen X (MX).

Collectively these chemicals are termed Disinfection By-Products (DBPs) which adds synergistic toxicity to the hundreds of other dangerous substances found in our water supplies.

The most common by-product of chlorination is a set of compounds known as Trihalomethanes (THMs).

Types of Trihalomethanes

The four main forms of THMs are chloroform, bromodichloromethane, dibromochloromethane, and bromoform.

The Maximum Contaminant Level (MCL) regulated by the EPA for the concentration of Total Trihalomethanes (TTHM) in treated water is 80 ppb (parts per billion).

Even with chlorine removed, THMs frequently remain and may pose health risks when ingested, inhaled via steam or absorbed via the skin.

Research on Trihalomethanes Risk to Humans

Several human studies have investigated the relationship between exposure to chlorinated drinking water and cancer.

Researchers designed these studies to specifically assess whether THMs or other organic compounds occurring in drinking water as a result of chlorination are associated with an increased risk of cancer.

In other words, the risks from the chlorinated water itself were not the focus of the research. Rather, it was chlorine’s spawn … the trihalomethanes and other DBPs that concerned scientists the most.

An American Journal of Public Health study showed an association between the bladder and rectal cancer and chlorination by-products in drinking water. (1)

Additionally, as outlined in the EPA’s List of Drinking Water Contaminants, long term exposure to THMs can also result in liver, kidney or central nervous system problems and an increased risk of cancer. (2)

As a result of research to date, the EPA classified trihalomethanes as Cancer Group B carcinogens (shown to cause cancer in laboratory animals). The EPA is currently studying whether the carcinogenic effects occur in humans as well. (3,4)

While these unwanted disinfection by-products are monitored by your local municipality, the regulations are likely not enough to protect you and your family.

Eliminating THMs from your Drinking Water

So, what can we do to eliminate the risks from trihalomethanes? Would doing so improve the overall quality of the water we use every day to a safe level?

Pitcher based water filters are a common way people improve the taste and smell of their drinking water. However, while they do remove chlorine, they do not remove THMs.

Finding alternatives to the large-scale addition of chlorine and other chemicals to municipal water supplies is critically important. However, picking up a readily available filter at Target does not easily solve this problem.

Fixing your home’s water requires a more comprehensive approach that starts with water testing.

After that, the best option available for improving water quality and safety is to install a whole house water filtration system that removes ALL contaminants while retaining valuable minerals — not just chlorine, but also trihalomethanes and other disinfection by-products before they can reach any and all faucets in your home.

Suggested Guidelines

When searching for the best whole house filter for your home, be sure to seek one that includes the following characteristics.

  • Has a multi-year long filter life (10+ years or 1,000,000 gallons).
  • It requires no regular maintenance.
  • Removes chlorine, chloramines, THMs, HAAs, other DPBs, fluoride, and heavy metals among other contaminants in a single tank.
  • Retains essential minerals.

From my research, very few whole house water systems meet these criteria! If you are in the market for this type of home appliance, I recommend taking a look at the Radiant Life Whole House Filtration System – Series 2, 4, or 6 (size depends on the square footage of your home).

For kitchen only water filtration, a biocompatible multi-stage purification system is an excellent choice.


(1, 3) EPA: Drinking Water Contaminants
(2) American Journal of Public Health, Volume 82, No. 7, July 1992.
(4) Environmental Working Group: Water Treatment Contaminants