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The first thing that comes to mind when people hear about chlorinated water is a public swimming pool or something similar. However, this chemical is also widely added to our drinking water. You may not even realize it, but you come into contact with chlorine every time you drink, bathe or clean your house. Here’s everything you need to know about chlorine in tap water.
Why is Chlorine Added to Drinking Water?
Chlorine is used to disinfect water. It kills or neutralizes pathogens, waterborne diseases, and etiologic agents, which could potentially cause cholera, typhoid fever, diarrhea, respiratory tract infection, kidney damage, or endocrine damage.
Hypochlorous acid and hypochlorite ion are both disinfection agents that are formed by the breakdown of chlorine in the water. Both of these substances comprise what is called free chlorine. They attack bacteria and viruses, leading to cell membrane damage and enzyme destruction. Because of this structural damage and subsequent bacterial oxidation, the microorganisms are killed and can no longer cause harm to the human body.
The process of chlorination takes place through the following steps:
- The microbial cell is targeted by chlorine disrupting the cell membrane.
- Vital cellular components are released from the cell.
- The membrane processes are terminated.
- The cell stops functioning, so it can no longer grow or cause disease.
Hypochlorous acid and hypochlorite ion behave differently. The first one carries no electrical charge, which is why it can cause oxidization very quickly. The second one is negatively charged, and so is the cell surface. Therefore, the process is similar to two charges that repel each other. The chlorination process takes up to half an hour. The quantity of each element in the chemical compound determines the acidity/alkalinity of the chlorinated water (pH). The treatment process can adjust the pH level, so it’s important that the treatment facility keeps the level within the normal range.
Is tap water chlorinated? In the majority of cases, it is. Chlorine may be added at different points during the water treatment (WT) process. The pre-chlorination step is performed in water treatment plants to prevent the growth of algae, bacteria, and slimes in subsequent WT processes. Also, iron and manganese oxidation (e.g., from a groundwater source) make it possible to remove these elements later in the process. It also means increased chlorine contact time.
Chlorination is also performed just before filtration or sedimentation (physical water treatment process). This is done to:
- manage biological growth
- remove iron and manganese
- stop an algal bloom
- control taste and odors
- remove color in drinking water
As the final step in the water treatment process, treatment plants may perform post-chlorination to maintain a constant concentration. Water treatment plants try to find ways to achieve quality standards with lower doses of chlorine disinfectant adequately. The process of post-chlorination aims to minimize the amount of disinfectant added at the chlorine injection facilities. Therefore, chlorine levels in drinking water may vary depending on the water treatment facility.
As has been shown in a large number of studies, chlorination has a proven, highly satisfactory performance as a disinfectant. A leading advantage of this type of water treatment is efficacy against waterborne pathogens. However, microbial inactivation remains incomplete, with a slight concentration of organisms remaining in the water. Moreover, there have been some health concerns regarding chlorination.
Even though there are new emerging technologies, it is unlikely that the US will stop using chlorination to disinfect public water supplies anytime soon. All you can do is improve on the quality of the water after chlorination, which is where High Water Standard comes to the rescue with osmosis system installation. Order a filtration system to stop consuming any residual chemicals and microorganisms in your tap water. With a great system in place, you can be sure that whatever water treatment facility your district uses, you will be safe.
How Long has U.S. Drinking Water been Chlorinated?
Technically, chlorine was discovered, in 1774, by a Swedish pharmacist Carl Scheele in a small experimental laboratory. However, it was only first used as a germicide in Austria, in 1847, and as a water disinfectant in London in 1850.
After a series of debilitating cholera outbreaks John Snow, an English physician and a leader in the development of medical hygiene determined the cause of transmission. His investigation led to the conclusion that diseases such as cholera, typhoid, fever, and diarrhea were waterborne, and that water that came directly from the river was not safe. Later, in the early 20th century, chlorine in drinking water was suggested to be used for troops in the field.
Here is a detailed timeline of how the United States adopted the practice of adding chlorine to its water supplies:
- 1908 – Jersey City, NJ. Similar to many American cities, at that time, Jersey City had a typhoid fever outbreak, with 21.4 reported cases per 100,000 people. Dr. John L. Leal had a novel, inexpensive solution: to use full-scale water chlorination, using sodium hypochlorite.
- 1908 – Chicago, IL. Chicago’s union stockyards had been using filtered drinking water from the Bubbly Creek. But the animals failed to thrive unless they were given Chicago municipal water. George A. Johnson tried using the chloride of lime germicide, and it became cleaner than the Chicago water supply.
- 1910 – Youngstown, Ohio. C. R. Darnall’s invention, the mechanical liquid chlorine purifier for water systems, was the prototype for the current water chlorination technology.
- 1914 – The Treasury Department drafted the first standards for drinking water. The bacteriological standard required the use of chlorine in drinking water to fulfill the rules. Water had to be free from harmful effects and an offensive look, taste, or smell.
- 1920s-1930s – Drinking water filtration and chlorination had virtually eliminated epidemics of waterborne diseases in the U.S.
And here you can see the course of the crude death rate for infectious diseases throughout the 20th century.
But what type of chlorine is used in drinking water in the United States these days? The table below shows how frequently certain water treatment methods are used.
| Disinfectant | Large Systems | Small Systems Using Groundwater | Small Systems Using Surface Water
|
| Elemental Chlorine | 84% | 61% | 82% |
| Sodium Hypochlorite | 20% | 34% | 17% |
| Chloramines | 29% | – | 2% |
| Chlorine Dioxide | 8% | – | 6% |
The totals may be greater than 100% since some systems may utilize several types of disinfectants.
As you can see, chlorine in tap water is practically impossible to escape. Let’s examine some of the potential health risks associated with continually drinking chlorinated water.
Is Chlorine Water Safe to Drink?
In compliance with the U.S. Environmental Protection Agency (EPA) regulations, water disinfection is performed with a very small amount of chlorine. Sources claim that the regulations are compiled with public safety in mind and safe chlorine levels in drinking water cause no substantial health risk.
That said, many Americans are still concerned about the quality of drinking water and have been for quite some time. Gallup polls provided us with more insight – it was found the biggest environmental concern is drinking water pollution. Since the maintenance of the nation’s supply of fresh water is such an important topic, let’s examine the effects of chlorine in drinking water.
Chlorine can be toxic, not only for microorganisms but for humans as well. By itself, chlorine poses minimal health risks because the allowable chlorine levels in drinking water are very small. Direct exposure can lead to irritation in the:
- eyes
- nasal passages
- respiratory system
However, it doesn’t stop at these reactions. Chlorine reacts chemically with organic matter, and the byproducts of this reaction include trihalomethanes. It’s hard to say what amount of THMs are generally present in water since it can vary depending on the season and where the plant originally gets raw water from.
The epidemiological evidence suggests a link between exposure to THMs and adverse outcomes, particularly cancers of vital organs. Based on animal data, for the various tumors, THM poses a carcinogenic risk, particularly with increased risk of bladder, colon, and rectal cancer. For instance, a recent study evaluated the relationship between bladder cancer and THMs. They found a modest association between them and expressed concern based on toxicologic evidence.
THM exposure is also harmful to pregnant women. Internal doses throughout an entire pregnancy negatively affect fetal growth, which is not something anyone would want to risk. Other studies also found that elevated maternal blood THM levels may lead to low birth weight, reduced birth length, and increased risk of SGA (small for gestational age). Obligatory in the scientific community, they also added that trimester-specific exposure needs further research.
Chlorine ppm in drinking water indicates that chlorine that was added for disinfection has created residual chlorine. The growing public awareness of the hazardous effects of water disinfection has prompted people to find ways to remove free chlorine residuals as well. The measure of free chlorine in drinking water ppm is 0.5, which is a sufficient amount for maintaining water quality. However, it is considered an additive and is not recommended for consumption.
Most of the studies focus on long-term exposure. While chlorine in drinking water side effects are not immediate, they are cumulative. The nature of the problem is rooted in the fact that people consume chlorinated water over the course of many years. So, even though the health hazard is not urgent, the magnitude of the problem is severe. The vicinity of a water treatment plant affects the quality of water you receive. The EPA’s yearly Consumer Confidence Report allows consumers to get information on a specific water supplier. If you know what impurities your local water has, you can start looking for solutions for your specific needs.
You can also look up the Chlorine International Chemical Safety Card for unbiased information on the chemical. As you will see on the card, chlorine is far from harmless: the effects of short-term to long-term or repeated exposure don’t instill confidence in consumers. The good news is that you don’t have to spend a fortune to avoid chlorine exposure. High Water Standard prices are affordable and support our mission of bringing clean water to as many households as possible.
What Can You Do to Lower the Amount of Chlorine in Drinking Water?
Some cities, or even different parts of the cities, have varying chlorine levels in the water supplies. A resident who can only access tap water, with high chlorine concentration, has to look for effective and affordable solutions.
If you have too much chlorine in drinking water, there are several methods of chloramine removal, which can be put into three general categories:
- Evaporation – you can get rid of some levels of chlorine by letting it sit at room temperature, which will allow the gas molecules to escape. If you want to speed up the process, you can expand the surface area, since it will increase air exposure of chlorine molecules. However, this method does not work with chloramines or any other disinfectant.
- Chemical Neutralization – if you are wondering how to remove chlorine in drinking water through chemical reactions, you should know that not all methods are worth your time. For example, sulfur dioxide is effective but toxic and difficult to work with. Other options like vitamin C, ascorbic acid, sodium thiosulfate, or sodium sulfite are safer choices. However, none of them remove all of the contaminants in the water.
- Filtration – lastly, you can use a water filter to remove chlorine. This is by far the best and most effective way to achieve dechlorination. You can choose between point-of-use (POU) and point-of-entry (POE) options depending on your needs. POU filters connect to one outlet and provide clean water only from that outlet in the house. POE filters supply clean water to the whole house. Bear in mind that the size of the filter must be appropriate for the amount of water to be treated.
One particular recommendation for a POU filter is a Granular Activated Carbon (GAC) filter. These are made from organic materials, with high carbon content, such as coconut shells, wood, lignite, and coal. The materials are slowly heated in low- or no-oxygen settings, and it can remove most organic compounds. Carbon Block (CBC) filters work similarly to GAC filters. It effectively reduces the chlorine taste and odor, as well as removing other contaminants.
A POU system can also benefit from a poly hard water conditioner. Polyphosphates are used to prevent contaminants from getting attached to the inner surface of the plumbing system. They are also used to reduce trace amounts of iron, manganese, lead, and copper.
The United States also employs the practice of adding fluoride to the water supply in order to fight off the bacteria that leads to tooth decay. The CDC bases its use of fluoridation on the fact that it positively impacts our health, by reducing the severity of cavities, and the need for fillings and teeth removal. But it turns out that topical fluoride application should be encouraged instead of consumption. And fluoride consumed internally can accumulate in bones and cause thyroid problems.
Getting rid of chlorine from water is even less difficult than eliminating fluoride. The types of filters mentioned below are considered water filters that remove fluoride and chlorine alike. So, by purchasing any of them, your water will be protected from both compounds.
Even if it is a small amount of fluoride, it is fair to expect your filter to remove it from the drinking water. To meet this need, the Water Quality Association suggests several types of treatment, so that you can have fluoride and chlorine water filter in one place:
- Distillation – while it is technically not a filter, it is still a very effective way to remove just about anything from water, fluoride and other contaminants included. The water vapor will perfectly clean the water, unfortunately, most of the time, it is not feasible to perform this activity at home.
- Strong base anion (SBA) exchange resins can remove both strong and weak acids. However, they are suitable for industrial use only and cannot be easily found.
- Activated alumina media – these filters are installed to reduce fluoride, arsenic, and selenium in drinking water without adding any harmful chemicals or substances. This option is better suited for rentals, meaning if you can’t make permanent changes to the water system in the home.
- Reverse osmosis is the common option in the chlorine water filter market due to its effectiveness. RO membranes can retain 99% of all contaminants, including chlorine, chloramines nitrates, sulfates, fluoride, bacteria, pharmaceuticals, and much more. The system successfully improves the taste, odor, and color of drinking water, and is essentially better than bottled water.
Removing Chlorine with High Water Standard Filters
You shouldn’t just accept the fact that all tap water will have chlorine in it. Contact High Water Standard to equip your home or office with the best filtration system that meets your needs. Once installed, our filters will serve you for a very long time, removing harmful chemicals and providing you with clean drinking water. With just one system, it’s extremely easy to have safe water running from every faucet in your home
