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  • Trihalomethanes (THMs) are chemical compounds found in drinking water as disinfection by-products that can be harmful to health, increasing cancer risk.

Imagine pouring a fresh glass of water from your tap at home, anticipating the cool, refreshing hydration that only water can provide. Now, imagine that the same seemingly pure water contains invisible chemical compounds potentially harmful to your health. It's not a pleasant thought, is it? Today, we're going to discuss one of these compounds that's likely swimming about in your tap water: trihalomethanes (THMs).

You might be asking, "Trihalo-whats?" It's a mouthful, we know. But trihalomethanes (or THMs for short) are something you definitely want to know about. They're a form of disinfection by-product, compounds that form when disinfectants used in water treatment (like chlorine) react with organic matter. While these disinfectants are important for killing bacteria and other pathogens in our water, they may have unintended health consequences.

And the presence of THMs in our water isn't just a minor inconvenience—it’s also a significant health risk.

THMs have been identified as potential carcinogens, which means they could possibly lead to cancer. That's a pretty big deal, isn't it? The idea that something in our water could increase our risk of developing cancer is a bit unsettling, to say the least.

So, buckle up as we dive into the world of THMs—what they are and why they're not exactly the guests you want in your drinking water.

What are Trihalomethanes?

Trihalomethanes (THMs) are a group of chemical compounds that are formed as disinfection by-products (DBPs). Understanding what they are is the first step in making wise choices about how you handle your drinking water.

Disinfection by-products like THMs are formed when disinfectants—used to treat our water and kill off any harmful bacteria or pathogens—react with organic compounds. These disinfectants are usually chemicals like chlorine or chloramine, and the organic materials could be anything from plant material to substances resulting from bacterial activity.

Some common THMs found in drinking water include chloroform, bromoform, bromodichloromethane, and dibromochloromethane. Each of these compounds is made up of carbon, hydrogen, and one or more of the halogens: chlorine or bromine. They might sound scary, but these compounds are actually quite common in many of our water systems.

Contamination Facts







It's an unfortunate reality that THMs are widespread in our water supply. You can find these sneaky chemical compounds in various water sources including tap water, groundwater, surface water, and well water. They're not picky about where they set up shop, and that's part of what makes them such a concern.

So, what about the concentrations of THMs in drinking water? These can vary quite a bit, depending on the levels of organic matter in the water and how much disinfectant is used in the drinking water disinfection process. Some days, the concentrations might be lower, while other times, they might spike. That's why it's so important to have a way to filter out these unwanted guests from your water.

Simply put, THMs are more common in our water treatment systems than we'd like to think. They're in different types of water and their concentrations can fluctuate. But by knowing this, we can take steps to reduce their presence in our drinking water. Stick with us as we dive into the health risks associated with THMs.

Health Effects of Trihalomethanes

The general population will not experience any acute health impacts due to the presence of THMs in their drinking water. But long-term exposure to THMs has been linked to a variety of negative health issues including an increased risk of certain types of cancer, like bladder and colon cancer. It's also been suggested that these chemicals can have effects on the central nervous system, affecting how our brains and nerves function. These are serious health risks that make THMs a significant concern for public health.

Exposure to THMs can come in various forms. Ingestion of contaminated water is an obvious route, but did you know that, like many contaminants, you can also be exposed to THMs while showering? Hot water from the shower can cause THMs to be released into the air, where they can be inhaled. These chemicals can also be absorbed through the skin (dermal exposure) when we bathe, shower, or swim in contaminated water.

So, while we might often think about the quality of our drinking water, it's important to remember that it's not just about what we ingest. We also need to be mindful of the water we use for showering and bathing.

THMs present a variety of health risks, but knowledge is power. By knowing what these chemicals are, where they come from, and how they can affect us, we can make informed decisions about how to protect ourselves and our loved ones. Up next, we'll delve into what the EPA and other regulations say about THMs.

How does Clearly Filtered do at Removing Trihalomethanes?

Clearly Filtered Products that target Trihalomethanes

Removal Rate

Water Pitcher Filter

> 99.80%

Under the Sink Filter


Refrigerator Filter


Water Bottle Filter

> 99.98%

Clearly Filtered Can Help

THMs are a widespread issue in our water treatment plants, and they're not something to be taken lightly. From tap water to groundwater, surface water, and well water, THMs have found their way into our everyday lives.

We've discussed the potential health risks associated with THMs, like cancer and effects on the central nervous system, which makes their presence in our drinking water a public health concern. And while regulations exist, there's an ongoing debate about whether they truly go far enough to protect us.

But it's not all doom and gloom. You're not powerless in this situation. By opting for a reliable water filtration system, you can significantly reduce the levels of THMs in your drinking water and protect yourself and your loved ones.

So, what's your next step in the journey towards safer drinking water? We encourage you to explore Clearly Filtered's range of products. We're committed to providing water filtration solutions that truly make a difference, helping you to lower THM levels and improve your overall water quality.

Remember, every drop of water you consume matters. Don't compromise on your health. Choose Clearly Filtered, and commit to a cleaner and safer hydration experience today.

Get complete confidence in your water