What's on Tap: Chlorine in Drinking Water


Chlorine is a chemical element and a powerful disinfectant that is commonly used in municipal water treatment plants to kill bacteria and other harmful microorganisms. Its noticeable taste and odor is often associated with swimming pools because chlorine is also a common pool cleaner.


Its power to inactivate or destroy bacteria and microorganisms has made chlorine a popular method for treating water. While not naturally present it water, it began being added to water in the late 19th and early 20th century because it was found to be an effective, practical and affordable disinfectant. Today, it continues to be a standard in water treatment as a way to reduce waterborne infectious disease transmission.


Dry, itchy skin is the most common symptom of chlorine exposure and is typically tied to water used in showers and pools but chlorine poisoning can happen if too much is swallowed or inhaled. Chlorine poisoning can affect the respiratory, digestive and circulatory systems, with symptoms ranging from mild to serious.

Respiratory system symptoms:

  • Difficulty breathing
  • Fluid in the lungs

Digestive system symptoms:

  • Burning in the mouth
  • Swelling of the throat
  • Throat pain
  • Stomach pain
  • Vomiting
  • Blood in the stools

Circulatory system symptoms:

  • Changes in the pH balance of your blood
  • Low blood pressure
  • Serious injury to the eyes, including burning and irritation (temporary vision loss can occur in extreme cases)
  • Skin damage, potentially resulting in tissue damage, burns, and irritation


Purification technology has advanced and new water treatment options have been developed; yet a very powerful chemical is still being in our drinking water. Similar to the concerns regarding the use of fluoride in water, some people question the continued used of chlorine as a disinfectant. Part of the concern is that it's not uncommon to find more chlorine in tap water than is recommended as safe for a swimming pool, and because high quantities of chlorine cause poisoning with severe symptoms, there's doubt about the safety of exposure over the long term. The effects of using chlorinated water long term are only recently being documented, and there is a lot of well-founded concern about chlorine. According to the U.S. Council of Environmental Quality, "Cancer risk among people using chlorinated water is as much as 93 percent higher than among those whose water does not contain chlorine." When chlorine is added to our water, it combines with other natural compounds (organic material) to create chloroform, trihalomethanes (THMs) and other "chlorination disinfection by-products" (CDPs), all of which have been strongly linked with incidence of cancer. While the EPA and World Health Organization continue to support chlorine as a water disinfectant, by being an informed consumer you can decide for yourself whether you want to drink chlorinated water or use a filtration system to remove it.


In compliance with the Safe Drinking Water Act of 1974, the EPA has set four milligrams per liter as the level of chlorine in drinking water at which no adverse health effects are likely to occur. This is a non-enforceable health goal, based solely on possible health risks and exposure over a lifetime, with an adequate margin of safety.


If you're concerned about the quality of the water in your home, there are a few ways to learn about its safety:

  1. Test the water yourself. Using an at-home kit, you can take a water sample and mail it to a lab for analysis. An important note: Not all test kits are the same. Make sure the kit you purchase will test for the contaminants you are concerned about.
  2. Request a water quality report. All public water systems in the U.S. are required routinely test contaminant levels. They are also required to provide customers with an annual Consumer Confidence Report that details the water quality in your community, just ask for a copy.
  3. Call the EPA's Safe Drinking Water Hotline for more information about drinking water safety in your area: 1-800-426-4791.


If you have decided that you do not want chlorine in the water you drink, clean or bath with, a filtration system can easily reduce its presence, while keeping it safe and tasting great. A whole-home filtration system will purify all the water that comes out of every tap, faucet, and showerhead in your home, ensuring every drop of water used for cooking, drinking, and bathing is free of chlorine and other contaminants. Under sink and counter top systems even economical pitchers are also effective point-of-use systems. Countertop and pitcher filters are especially ideal in apartments and dorms because they give you all the benefits of clean water without having to alter the plumbing system.


While there are a variety of filters on the market, these three systems are top performers:





To maintain the effectiveness and ability to reduce chlorine's presence from your water, it's important to regularly replace the filter or filter cartridge. When a filter becomes overused or out-of-date, contaminants can slip through and make their way into your water. To keep your water safe, it's important not to put off replacing it. There are four effective ways of knowing when it's time to replace your water filter:

  1. Follow the manufacturer's recommendations. Their specified replacement timing will err on the side of caution so you can be assured that your water quality will always be safe.
  2. Measure usage. Install a filter measurement meter or filter monitor that connects to the incoming water line that feeds the filter system and measures the number of gallons that pass through. Then using the manufacturer's recommended usage limit, program the monitor to alert you when you've reached the allowed number of gallons. You'll know exactly when it's time to replace the filter.
  3. Read your water bill. If your home is supplied with municipal water, your water bill will tell you exactly how much water is used monthly. Compare your actual usage to the manufacturer's recommendation and plan the replacement accordingly.
  4. Monitor manually. If you have non-municipal water, the most cost effective method is to monitor your filter manually either with your palate or a water testing kit. Start with routine water tests that look for lead, microorganisms and other contaminants to verify whether your filters are still removing them. For drinking water systems, simply fill a glass with water and check the flavor yourself. You'll be able to see or taste when the filter is exhausted and no longer purifying your water because the water flavor will be unpleasant.


For answers to chlorine-related questions, recommendations on the best filter for your home, or general drinking water questions, contact us.