How To Remove Trihalomethanes (THMs) From Drinking Water? Does the Berkey remove THMs?

How To Remove Trihalomethanes (THMs) From Drinking Water Does the Berkey remove THMs

THMs are a group of chemicals that are formed in the water along with other disinfection by-products. The chemicals included are chloroform, dibromochloromethane, bromodichloromethane, and bromoform. It is formed when chlorine and other disinfectants people use in the water react naturally with the inorganic and organic matter in the water.

The United States Environmental Protection Agency (US EPA) has created the Stage 1 Disinfectant and Disinfection By-products Rule to regulate the THMs at a maximum average level of 80 parts per billion each year.

Some of the main health concerns of THM exposure in drinking water are an injury to the kidneys, liver, increased risk of the bladder, and malfunction of the central nervous system.

Thus, in this article, we will discuss how we can minimize THMs in drinking water. Also, we will tackle the standards and initiatives set forth by the authorities in making drinking water safe for consumption. 

The Rate of the THMs in the Water Supplies

There are various studies conducted since the 1970s to check the presence of THMs in drinking water. In the recent study done by the US EPA, they have confirmed the presence and the dangers posed by the THMs in the water.

Its formation is due to the chlorine-based disinfectants' reaction with the organic materials present in the untreated water supplies.

In general, organic contaminants come from the natural materials in the environment. Examples are from the leaves, decaying plants, and other dead materials at the surface level of the water.

Such organic material is usually discussed and measured as the total organic carbon (TOC). The amounts of the THMs formed and usually related to the amount of TOC plus the used disinfectant.

Some of the reactions that form THMs during the treatment, distribution, and storage within the drinking water systems are influenced by time, pH level, and temperature.

Testing, Reporting, and the Exposure Routes for the THMs

In 1979, the US EPA required the public water systems that generally serve around 10,000 clients to have the water tested. They require them to have the water undergo examination, and there must be reports published regarding the THMs levels.

How To Remove Trihalomethanes (THMs) From Drinking Water Does the Berkey remove THMs

The initial limit adopted by the EPA was 0.1 parts per million (ppm) total combined THMs.

Meanwhile, in 2001, the EPA adopted a more protective maximum contaminant level (MCL) which applies to all community sizes and even the non-transient water systems of 0.08 ppm total combined THMs.

Also, the US EPA has adopted the regulatory goals (MCLGs) for the bromodichloromethane (zero) for bromoform (zero), for dibromochloromethane 0.06 ppm.

In the total THM concentrations, the chloroform must be included. However, this time, the MCLG or the MCL must not be included anymore.

The main routes of exposure to the THMs in the drinking water are through the water itself. The studies found that the major exposure route can be linked to bathing, showering, cleaning the house, washing clothes, and cleaning the dishes.

Exposure of People from THMs in Drinking Water

People can be exposed to THMs whenever they drink water that is contaminated by such compounds. Apart from this, one can get exposed to THMs whenever they take a shower, bath, or other activities to expose their body to the contaminants.

The THMs can evaporate from the tap, and the user can inhale them whenever they shower. Also, the skin can absorb it whenever they take a bath.

As such, the authorities have considered these routes of exposure in the crafting of the guidelines. As long as the water meets the total THMs levels, it is considered safe for domestic uses: bathing, drinking, food preparation, house cleaning, and others.

Potential Complications of High THMs levels in the Drinking Water

Indeed, the four by-products of chlorination are considered to belong to Cancer Group B carcinogens. According to studies, these can cause cancer among laboratory animals.

How To Remove Trihalomethanes (THMs) From Drinking Water Does the Berkey remove THMs

Today, trihalomethane or chloroform is the most common in the majority of water systems. Meanwhile, dibromochloromethane can cause the most serious cancer case, followed by the bromoform and the chloroform.

While the THMs can contribute to the outcome of birth, there can also be various factors involved. Pregnant mothers must be aware of the THMs level in their water and take precautionary steps in its reduction.

The laws in the United States currently limit the concentrations of the said chemicals to 80 ug/l.

Health Risks

THM exposure's main health concern is having an injury to the kidneys, liver, increased risk of the bladder, and malfunction of the central nervous system.

Nowadays, more studies show the association of THM exposure plus various reproductive issues. Examples are fertility, gestational and menstrual disorders, stillbirth, miscarriage, and even congenital disabilities.

Also, THMs are one of the main causes of cancer due to their possibility of producing human carcinogens.

The USA EPA estimates that 3-4 cancer cases can occur among every 10,000 people. This is true for people who consume 2 liters of water which contains only 0.1 ppm of chloroform every day for 70 years.

For some studies, they use a shorter period as an example. This is because it is uncommon for the person to use the same water supply for a complete lifetime.

It is not true that the inhalation of the THMs is less dangerous than its ingestion of the same amounts.

THMs Regulations

The US EPA considers the all-encompassing revision of the regulations which cover the disinfection by-products or the DBPs. The THMs limit can be lowered down to 80 ug/l, and it can have three more categories of DBPs.

This standard can now replace the standard set today to a maximum allowable level per year of 100 parts per billion for the large surface water public systems.

Haloacetic acids

The haloacetic acids are just like the THMs, and these are the byproducts of chlorination. Examples are dibromoacetic acid, monobromoacetic acid, monochloroacetic acid, trichloroacetic acid, and dichloroacetic acid. It is expected to have 60 ug/L of MCL for total haloacetic acid. If there are excessive amounts of haloacetic acids, it can cause liver and nervous system malfunctions.


The Chlorite must be regulated to MCL set at one mg/l. If there are excessive amounts, then it can cause hemolytic anemia.


Bromate is another regulated DBP that is being limited for the systems using the ozone. It is expected to have a level of only ten ug/l. When there is an excessive level, it can lead to hearing, kidney, and gastrointestinal effects.


Another method to avoid the THMs in the water is through something other than the gas or the hypochlorites as the disinfectants. Some of the possible disinfectants are chlorine dioxide, chloramines, UV light, and ozone. However, they can also produce some harmful by-products after that.

Removal of the THMs in the Water

The levels of the THM increase with time, temperature, pH level, and the level of the precursors available. The precursors are the organic materials that react with chlorine to produce THMs.

One way to reduce the level of the THM is to decrease the precursors and chlorination in the filters.

Indeed, there are lots of precursors that are present in the process of filtration. As such, it is best to reduce it as the chlorine gets in contact with the water. If it requires oxidation before filtration, alternative disinfectants like peroxide and potassium permanganate can be considered. However, this is not the only option if prechlorination is needed to get the desired CT values.

Removal of Precursors: Enhanced Coagulation

According to the EPA, the best available technology for controlling the THM at the treatment plants is by removing the precursors by enhanced coagulation.  

Enhanced coagulation is the process of optimizing the process of filtration to maximize the elimination of the precursors. The removal is improved by reducing the pH level as low as 4 to 5, increasing the coagulant's feed rates, and using the ferric coagulants instead of the alum.

Carbon Filter

One of the easiest ways of eliminating the THMs in the water is through activated carbon or charcoal. Also, try this on a water pitcher with a carbon filter. Interested homeowners can also install carbon filters in their tap source or put them on their bottled water. 

Check that the bottled water’s supplier is a member of the International Bottled Water Association to be safe.

One can use the activated carbon in the whole house water filtration system. Also, it can be used as a backwashing system that features not using requiring the changing of the cartridge regularly.

In using a water filter, make sure that it is certified to remove the THMs. Make sure to follow the instructions on its replacement which is recommended by the manufacturer.

Reverse Osmosis Systems

Indeed, a reverse osmosis water filtration system can do an excellent job in removing the THMs in the water.

Reverse osmosis is when the dissolved inorganic solids, just like salts, are removed from the water. This can be possible by household water pressure that pushes the tap water through a semipermeable membrane.

According to studies, reverse osmosis systems can remove the lead, THMs, fluoride, chlorine, chloramine, pesticides, detergents, etc.

When the household water pressure pushes the water through the reverse osmosis system membrane plus other filters, the impurities will be filtered out. Then, it will be flushed down the drain.

After that, it can have the ability to produce clean and good tasting drinking water.  

Water Softeners

The water softeners are also innovative devices that can help remove the THMs in the drinking water. 

The water softeners can effectively remove the magnesium, calcium, and other metals in the hard water. Then, it will result in soft water that can require less soap for the same cleaning effort. As such, soap will not be wasted with the mopping up of calcium ions.

Also, the soft water can extend the lifetime of the plumbs by eliminating or reducing the buildup of scale in the fittings or the pipes. Water softening can be achieved with the use of ion-exchange resins or the lime softening technique.

UV Systems

Ultraviolet or UV water purification is a type of energy that is found in the electromagnetic spectrum. It lies between the visible light and the x-ray.

Though the UV rays or lights cannot be seen with the naked eye, we are exposed to them each time we step outside under the sun's heat. UV light can be the main cause of sunburns.

The UV water purification systems use special lamps that can emit UV light of a particular wavelength. With this, it can disrupt the DNA of the microorganisms.

The UV light waves are also called the Germicidal Spectrum or frequency. As the water passes through a UV water treatment system, the living organisms are exposed to UV light, which attacks its genetic code. It rearranges the DNA or the RNA and eliminates the microorganism’s ability to reproduce and function properly. As such, it cannot infect or even have contact with other organisms.

This process can be simple, yet it is very effective. It can destroy around 99.9% of harmful microorganisms without adding any chemicals to the water.

Berkey Water Filtration System 

 According to the Laboratory tests, the Berkey products can reduce the Trihalomethane (THMs) of up to 99.8%. 

Black Berkey® Elements dramatically reduce trihalomethanes, inorganic minerals, heavy metals, pharmaceuticals, pesticides, VOCs, petroleum products, perfluorinated chemicals, rust, silt, sediment, radiologicals, and more.

The Berkey Water Filter has seven various products, and you can choose any unit based on your needs. 

Travel Berkey Water Filter 

How To Remove Trihalomethanes (THMs) From Drinking Water? Does the Berkey remove THMs?

For travelers who are always on the go, they can have the Travel Berkey Water Filter. This compacted system is excellent for on-the-go activities and emergencies. 

It has a storage capacity of 1.5 gallons and perfect for small homes. Furthermore, it can serve 1 to 3 people for everyday use. 

Berkey Light Water Filter 

How To Remove Trihalomethanes (THMs) From Drinking Water? Does the Berkey remove THMs?

For a lightweight alternative to a water filter, you can grab the Berkey Light Water Filter. This one is affordable and more portable than the stainless steel counterpart. 

The Berkey Light Water Filter is made from a non-BPA/BPS co-polyester, which does not leach with the water. 

Furthermore, it has a capacity of 2.75 gallons or 10.4 liters of water. In regular use, it can already serve around 1 to 5 people. 


In a nutshell, there are various methodologies to remove THMs in drinking water since it poses various health risks to people. 

Now, researchers are continuing to study the THMs and other disinfection byproducts to discover methods to minimize and eliminate them from the drinking water.

Surely, there will be new changes in the technology and the drinking water regulations since there will be more information that will become available to the public in the coming years.

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