How to Remove Trihalomethanes From Drinking Water - Water Wisdom - Mayu Water Blog

How to Remove Trihalomethanes From Drinking Water


Cameron-Leigh Henning

 on June 27, 2022. 
Reviewed by 

Romi Hector

Woman standing in hallway with concrete pillars looking disgusted by ceramic jug

Trihalomethanes (THMs) formwhen chlorine reacts with the organic matter in water. The four trihalomethanes are bromoform, bromodichloromethane, chloroform, and dibromochloromethane.

Trihalomethanes are dangerous at elevated levels and have been shown to increase the risk of cancer, miscarriages, pregnancy issues, and heart, lung, liver, kidney, and central nervous system damage. In this post, we have outlined the best methods for removing trihalomethanes from yourdrinking water.

How Are You Exposed to THMs in Drinking Water?

You can be exposed to trihalomethanes by consuming water through a public water supply, using tap water for cooking, or absorbing it through the skin. Trihalomethanes vaporize into the air, so exposure to these compounds can also occur through inhalation, especially when showering and bathing.

How to Get Rid of THMs in Water

There arevarious methods you can use to remove trihalomethanes from your drinking water.

Enhanced Coagulation

This method is the best option for controlling the level of THMs at a water treatment plant and removing the precursors by enhancing coagulation. The enhanced coagulation process optimizes the filtration process to maximize the elimination of precursors. This is done by reducing the pH level to as low as 4, using ferric coagulants instead of alum, and increasing the coagulant’s feed rates.

Carbon Filters

This is one of the most convenient ways to eliminate THMs in your tap water. Carbon filtration uses charcoal or activated carbon to remove contaminants. Carbon filtration can be done using a water pitcher with a carbon filter or installing carbon filters on your taps.

Activated charcoal can also be used in your whole house's water filtration system. When purchasing acarbon filter, ensure it is certified to remove THMs.

Reverse Osmosis

Reverse osmosis water filtration systems also work well to remove THMs from water. Thereverse osmosis process involves water being pushed through a semipermeable membrane that filters out unwanted particles and contaminants. Reverse osmosis removes THMs, lead, chlorine, fluoride, pesticides, chloramine, detergents, etc.


Boiling your water is a simple method to drastically reduce the levels of trihalomethane in your water. Boiling water for one minute can reduce the trihalomethane concentrate by 75 percent. Boiling water for five minutes removes 100 percent of the trihalomethanes.

How Do I Know How Many THMs Are in My Water?

You can test your water for trihalomethanes using the following methods.

Observational Self-Testing

This testing is done through simple observations that you can make using your own senses like taste and smell. The obvious signs of high trihalomethane levels are a strong chlorine smell or the water smelling like diluted pond or lake water.

DIY Water Testing

After observing the water, you can use a testing kit to confirm if your observations were correct. Most testing kits consist of dip tests that will allow you to monitor the THM levels in your water.

Information Water Testing

This is done by an accredited water testing laboratory. You can order a testing kit to prepare a sample to submit to a lab. By using a lab, you can trust that a certified water expert will analyze your sample.

Certified Water Testing

This option involves a water professional visiting your home to prepare the sample and then sending it to a lab for testing. This form of testing will give you the highest level of assurance in the accuracy of your test results. This option can also be used in legal cases.

In Summary

If you have high levels of trihalomethanes in your drinking water, you can begin by using the above methods topurify your water. Carbon filtration is considered to be the most thorough when it comes to removing chemical compounds. Other options consist of working with an authority or water company to flush the lines.

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