HAA5 (Haloacetic Acids) in tap water

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Toxicity Rating
Health Effects

Long-term exposure to elevated levels of HAA5 has been associated with bladder, colon, and rectal cancer, as well as liver and kidney issues

The legal limit is
Health Guideline
0.1 ppb
what is considered unhealthy
Legal Limit
60 ppb
What is HAA5?
HAA5 is a group of harmful disinfection byproducts (DBPs) known as haloacetic acids (HAAs). HAAs form when disinfectants like chlorine or chloramine interact with natural materials found in water. HAA5 is made up of 5 haloacetic acids: dibromoacetic acid, dichloroacetic acid, monobromoacetic acid, monochloroacetic acid, and trichloroacetic. HAA5 is the only group of haloacetic acids regulated by the U.S. Environmental Protection Agency (EPA), and HAA5 does not alter the appearance, smell, or taste of water.
What are HAA3, HAA6Br, and HAA9?
Any numeral following the acronym HAA references the individual compounds that make up a group of haloacetic acids. HAA3 is made up of bromodichloroacetic acid, dibromochloroacetic acid, and tribromoacetic acid. HAA6 is the same group of compounds that form HAA5, along with bromochloroacetic acid. HAA9 is simply HAA6 and HAA3 together.
What are disinfection byproducts (DBPs)?
DBPs, like haloacetic acids, are the result of chemical reactions that occur when matter in water and disinfection agents, such as chlorine, interact. Hundreds of DBPs exist, but haloacetic acids (HAAs), trihalomethanes (THMs), chlorite, and bromate are common DBPs associated with tap water.
DBPs vary based on a variety of factors including the water’s organic matter and the disinfectant used to treat said water. The U.S. EPA has set Maximum Contaminant Levels (MCLs) for HAA5, THMs, chlorite, and bromate to regulate the volume of DBPs found in U.S. drinking water supplies. The U.S. Food and Drug Administration (FDA) has set allowable levels of HAA5, THMs, chlorite, and bromate to regulate the volume of DBPs found in bottled water.
Why is HAA5 in my tap water?
HAA5 is found in tap water because 98% of tap water supplies in the U.S. are treated with chlorine to help prevent contamination. Water treatment is a delicate balancing act, and the volume of chlorine used to treat individual water supplies changes constantly in response to new and emerging contaminants and threats, damaged and aging systems, and other means of contamination including natural disasters like flooding and fires. Elevated levels of chlorine, as well as elevated levels of specific organic and inorganic matter in water, can be linked to elevated levels of HAA5.
Why is HAA5 in my tap water harmful?
Long-term exposure to elevated levels of HAA5 has been associated with bladder, colon, and rectal cancer, as well as liver and kidney issues. Some studies have shown possible harm to fetal growth and development, though results have been mixed. Pregnant women, children, and those with existing health problems should be extra cautious of HAA5.
How much HAA5 is safe and what is the MCL for HAA5?
The U.S. EPA has set a Maximum Contaminant Level (MCL) for HAA5 of 60 parts per billion (ppb) or 0.060 milligrams per liter (mg/L) as an annual average. Since this is measured as an annual average, HAA5 can exceed the MCL at any given time. The Environmental Working Group (EWG) points out that the current MCL for HAA5 set by the U.S. EPA does not fully protect against the risk of cancer and harm to developing fetuses.
Is HAA5 in bottled water?
Yes. While the EPA regulates tap water, the FDA regulates bottled water because it is classified as a food. The FDA allows 0.060 milligrams per liter (mg/l) of HAA5 in bottled water, matching the regulations set for tap water by the EPA.
How can I reduce HAA5 in my drinking water?
Clearly Filtered’s Water Pitcher with Affinity® Filtration Technology removes up to 99.9% of HAA5 from your tap water. Upgrade to our superior water filters so you never have to worry about haloacetic acids lurking in your water again. Remember, boiling water does not remove HAA5. As a matter of fact, boiling water increases the concentration of HAA5 in your water.
How does Clearly Filtered do at Removing HAA5 (Haloacetic Acids) in tap water?
Clearly Filtered with
Affinity Filtration Technology Product
Water Pitcher Filter
Under-the-Sink FIlter
Water Bottle Filter
Refrigerator Filter
HAA5 (Haloacetic Acids) in tap water Removal

1. American Chemistry Council. Chlorine and Drinking Water. https://chlorine.americanchemistry.com/Chlorine/DrinkingWaterFAQ/. Accessed April 1, 2021.

2. EWG Tap Water Database. Haloacetic acids (HAA5). https://www.ewg.org/tapwater/contaminant.php?contamcode=2456#. Accessed April 1, 2021.

3. U.S. EPA. National Primary Drinking Water Regulations. https://www.epa.gov/ground-water-and-drinking-water/national-primary-drinking-water-regulations. Accessed April 1, 2021.

4. U.S. FDA. Small Entity Compliance Guide: Bottled Water and Residual Disinfectants and Disinfection Byproducts. https://www.fda.gov/regulatory-information/search-fda-guidance-documents/small-entity-compliance-guide-bottled-water-and-residual-disinfectants-and-disinfection-byproducts. Accessed April 1, 2021.