What Is a Good Chlorine Level for Drinking Water?

Among the 71% of water on earth, only 3% is fresh water. And only 1.2% of the total water is drinkable. So, you can imagine how scarce pure drinking water is. This is why water supply agencies purify water from natural sources before delivering it to your home. Chlorination is a common process in water treatment.

So, what is a good chlorine level for drinking water? According to the EPA, 4 mg/L or 4 ppm of chlorine is safe for drinking water. If you intake too much chlorine in drinking water, it can be detrimental to your health.

Learn more about chlorination, its side effects, and how to test the level of chlorine in your drinking water.

What Is a Good Chlorine Level for Drinking Water?

Water from natural sources is often contaminated with microbes that cause diseases in humans and other animals. For example, salmonella is a common germ present in water from natural sources. It causes diarrhea, typhoid fever, etc.

To prevent drinking water from containing harmful microbes, public water supply organizations use disinfectants like chlorine or chloramine. These chemicals kill germs in water. But residue of these chemicals can remain in the water.

a Good Chlorine Level for Drinking Water

A trace of residue might not be deadly, but that should always be under a safe level. National and international organizations have specific guidelines about the safe chlorine level in drinking water. According to the World Health Organization, the safe level of chlorine in drinking water is less than 5 mg/L.

But the EPA guideline is a bit different. The EPA suggests that the chlorine level in drinking water should not cross 4 mg/L. It is wise to stick to the lowest level to be safe. So, we can say that 4 mg/L is a good chlorine level for drinking water.

Side Effects of Higher Chlorine Levels in Drinking Water

Drinking water that has a higher amount of chlorine than the safe level can have several side effects on human health. Check these out.

  • A sudden intake of high-chlorine water can cause a burning sensation and vomiting. 
  • If you continue to drink chlorinated water, the risk of asthma increases. The same happens when humans are exposed to hypochlorite or hypochlorous acid.
  • Excessive chlorine exposure can cause dermatitis. Various skin diseases will occur due to chlorinated water consumption.
  • Drinking chlorinated water increases the serum cholesterol level. It also increases the low-density lipoprotein or LDL level.
  • Adding chlorine to water for disinfection produces some disinfection byproducts. Trihalomethanes, chlorite, chlorate, haloacetic acid, etc., are the most common disinfection byproducts. Among them, trihalomethanes are considered carcinogenic. Drinking chlorinated water can cause bladder cancer.

Side Effects of Higher Chlorine Levels in Drinking Water

How to Test the Chlorine Level in Drinking Water?

When chlorine is added to water, the water has an unpleasant smell and taste. So, one of the easiest ways to determine if there is residual chlorine in water is the taste test. 

Check if there is any off smell in the water. Then, taste a few drops of water to see the taste.

You might have tasted pool water at some point. Chlorinated water will taste like pool water. The higher the level of chlorine, the stronger the taste. But this taste test doesn’t give the exact level of chlorine in water. So, we need to do a DPD test.

DPD, or Diethyl Paraphenylene Diamine, is an indicator that changes the water color depending on the level of chlorine present in it. To do this test, follow the steps below.

  • Step 1: Buy a portable chlorine testing kit. These kits are easily available.
  • Step 2: Take a DPD tablet in place in the left test chamber. Add a few drops of water you want to test in the same chamber.
  • Step 3: Crush the tablet. Then, pour more water into the same chamber to fill it up.
  • Step 4: Pour the same water into the middle chamber of the test kit. It is called the blank control chamber.
  • Step 5: Wait for some time. Then, check the color of the left test chamber with the middle control chamber. There will be different color markings associated with various chlorine levels. The corresponding color on the left chamber will indicate the chlorine level.
  • Step 6: If the color of the water on the left chamber is darker, repeat the process from step 2. But use the right test chamber this time. It is suitable for water with high chlorine levels.

How to Remove the Extra Chlorine in Drinking Water?

If the chlorine level in your drinking water is higher than the safe limit, you need to remove the residual chlorine from the water. The best way to remove chlorine and its byproducts is to pass the water through activated carbon filters.

How to Remove the Extra Chlorine in Drinking Water

Activated carbon has a higher surface area, and contaminants adhere to the surface easily. So, most of the contaminants will be eliminated from the water. Besides, the process will remove any VOCs from the water.

Frequently Asked Question

Check answers to commonly asked questions about drinking water chlorine levels.

Q: Can boiling water remove chlorine?

Yes. Boiling will remove chlorine from the water. Even if you keep the water at room temperature for a few days, the residual chlorine will evaporate. But boiling increases the rate.

Q: Does RO remove chlorine?

The use of RO filters has increased because they can remove chlorine and other disinfectants from water. You need to pass water through the RO filter, and it will effectively remove any chlorine in the water.

Final Words

Chlorination is a life-saving process that kills microbes responsible for waterborne diseases. But the process leaves some chlorine behind that can harm our health. So, it is necessary to figure out the safe chlorine level. 

Regarding what is a good chlorine level for drinking water, WHO and EPA guidelines say that 4-5 mg/L of chlorine is safe for drinking water. If you consume a higher level of chlorine, it will cause various diseases. 

They include dermatitis, asthma, cardiovascular issues, and even cancer. So, you should always be careful about the taste and smell of your drinking water. Test the chlorine level if necessary and try to remove the chlorine through filtration.

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