Everything You Need To Know About HAA5 In Your Drinking Water

by Brett Simpson / Jul 12, 2023
Everything You Need To Know About  HAA5 In Your Drinking Water

HAA5, a dangerous group of cancer-linked contaminants, has been found in tap water in all 50 states. Read on to discover what HAA5 is and how it gets into our water, why current regulations are being questioned, and the easiest way to protect yourself from this dangerous family of contaminants.


HAA5 Is An Acronym For A Specific Group Of Haloacetic Acids (HAAs) Found In Tap Water

To understand HAA5, you must first understand HAAs. HAAs is an acronym that stands for haloacetic acids. HAA5 is a collection of the following five haloacetic acids widely considered to be the most prevalent and potentially harmful in tap water:

  • Dibromoacetic acid (DBA)
  • Dichloroacetic acid (DCA)
  • Monobromoacetic acid (MBA)
  • Monochloroacetic acid (MCA)
  • Trichloroacetic acid (TCA) 

Multiple HAAs Have Been Linked To Multiple Types Of Cancer

So why should you be worried about HAA5 in your drinking water? Not only are these haloacetic acids legally allowed in tap water (to a certain, potentially dangerous level), HAA5 has been linked to multiple forms of cancer. Plus, it can be harmful to fetal growth and have developmental effects.

Additional health risks linked to HAA5 include increased risk of headache, nausea, sore throat, wheezing, shortness of breath, as well as liver damage and kidney problems. And longer exposure to contaminated drinking water may cause vomiting, diarrhea, and sore throat because HAA5 has the potential to burn the tissues of the human body. 

Now that you know just how dangerous it is, let’s talk about how HAA5 sneaks into our water and how likely it is to be lurking in your water right now. 


HAAs Often Form When Chlorine Is Used To Treat Water, Which Means Up To 98% Of Americans Could Be At Risk

98% of America’s public water supplies are disinfected with chlorine, which means 98% of our tap water has the potential to be contaminated with HAA5! 
You see, chlorine basically creates HAA5. How? Well, HAAs are what’s called disinfectant byproducts, or DBPs. As their name indicates, DBPs are created when a disinfectant, like chlorine, interacts with organic matter in water. So when chlorine mixes with certain matter found naturally in water, dangerous DBPs like HAAs and THMs (trihalomethanes) can form.

For example bromide, which can be found naturally in water, can react with chlorine to form bromine. Bromine can then react with other natural matter in water to form HAAs. See what we mean? You can think of it like mixing ammonia and bleach. Ammonia and bleach by themselves can be useful. But mixing them creates a deadly gas that can kill you.

Of course, mixing chlorine with water won’t kill you immediately… but as we said before, prolonged and excessive exposure to higher levels of HAA5 has been linked to multiple forms of cancer, among other things. 

Think of drinking water contaminated with HAA5 like smoking cigarettes. Smoking one cigarette probably won't cause cancer. The same goes with drinking a single glass of water polluted with HAA5. However, just like years of cigarette smoking can dramatically increase your cancer risk, so can regularly drinking HAA5-contaminated water.


Chlorine Is NOT The ONLY Source Of HAA5 In Water

While chlorine is the most common source of HAA5 in tap water, it’s not the only source. Here are some examples:

  • Other disinfectants. For example, chloramines, which are a combination of chlorine and ammonia that are sometimes used as an alternative to chlorine, can form HAA5 and other DBPs too.
  • Decay of organic matter. Organic matter like leaves, grass, and other plant matter can break down in water sources (like groundwater as well as surface water including lakes and rivers), then release natural compounds into water as it decays. Those compounds can then react with disinfectants to form HAA5 and other DBPs.
  • Algal blooms and breakdowns. When algae blooms, and when it dies, it can release organic matter into water that can later create DBPs. Algal blooms occur when there is an excessive growth of algae in a body of water, which can be triggered by things like warmer temperatures, nutrient pollution, and changes in water flow. And when algae dies or decomposes, it’s been suggested it releases dissolved organic carbon (DOC), which has been linked to DBPs, including HAA5.
  • Soil erosion. When heavy rainfalls, or other weather-related events, cause soil to wash into nearby water sources, organic materials can come along with it that can later react with chlorine to form DBPs.

HAA5 Is Legally Allowed In Our Tap Water

The U.S. Environmental Protection Agency (U.S. EPA), the organization responsible for regulating our tap water supplies by enforcing national drinking water standards, allows up to 60 parts per billion (60 ppb) of HAA5 in our tap water, without repercussions.

In other words, HAA5 is legally allowed in our tap water up to the EPA maximum contaminant level (MCL) of 60 ppb.


Up To 80% Of Americans Have Been Exposed To HAA5 In Tap Water

According to the Environmental Working Group (EWG), a nonprofit organization whose mission includes exposing drinking water pollutants, HAA5 is a nationwide problem: Since 98% of the drinking water in America is disinfected with chlorine, it’s no surprise HAA5 has been detected in tap water in ALL 50 US states

In fact, an analysis of drinking water samples from 2017-2019 revealed that contaminated water supplies reached approximately 286 million Americans. In other words, more than 4 out of 5 Americans could be drinking water polluted with HAA5.


Outdated EPA Regulations Allow Alarmingly High Levels of HAA5 In Our Drinking Water Today

The aforementioned EWG drinking water analysis dove even deeper:
It didn’t just find HAA5 in tap water in all 50 states, it found levels of HAA5 exceeding the EPA’s legal limit of 60 parts per billion in 26 states! 

And that’s scary because the current EPA legal limit was established in 1998. With a better understanding of HAA5 today, we now know this limit probably does not fully protect against the risk of cancer. Nor does it prevent harm to a developing fetus! 

Contamination Exceeds Peer-Reviewed Health Guidelines In All 50 States

To further protect Americans, EWG has established their own public health guidelines for water quality. And based on the organization's research as well as peer-reviewed scientific studies, its health guideline is 600 times stronger than EPA standards to protect the public from cancer. In other words, EWG experts suggest the U.S. EPA allows 600x too much HAA5 in tap water. 

Even worse, HAA5 levels in drinking water systems exceed the aforementioned EWG guidelines in all 50 states!


Other Countries Have Much Stricter HAA5 Limits Than The U.S. 

The fact that countries like Japan and China impose stricter limits than the U.S. on HAAs is concerning. At 0.1 parts per billion or less, these limits are far more stringent than the U.S. EPA’s standards, and in some cases, even more stringent than the EWG’s health guidelines! 

In fact, the U.S. EPA allows 600x-3,000x more haloacetic acids in tap water than Japan and China do! 

Recent Outbreaks & Updates

After proposing a limit on other cancer-causing PFAS in March of 2023, the EPA is now re-evaluating the legal limits on HAA5

Considering the growing number of cities around the US reporting high levels of HAA5 exceeding EPA limits, now is a good time to take a second look.

In addition to potentially reducing maximum contaminant levels of HAAs allowed in drinking water, the EPA may increase the number of regulated HAAs from 5 to 9 to provide better protection. A final decision is expected as soon as 2024.
While it’s great news to hear that the EPA is studying HAAs and may revise the legal limit of HAA5 in drinking water, what should you do to protect yourself today?

How To Protect Yourself From HAA5 In Your Water

Remember, HAA5 is not only allowed in tap water in all 50 states at potentially dangerous levels, it’s been detected in tap water in all 50 states. So how do you protect yourself from this cancer-linked family of contaminants?

Bottled Water Is Just As Dangerous As Tap Water

While the EPA regulates tap water, the FDA regulates bottled water because it is classified as a food. The FDA’s regulations match those for tap water by the EPA. In other words, bottled water can be just as contaminated as tap water!

Boiling Your Water Might Make Matters Worse

Boiling your water may not remove HAA5, either. As a matter of fact, boiling water may actually increase the concentration of HAAs, rather than decreasing them. In other words, it may make your water even more dangerous! 

Most Mainstream Filters Can Not Reduce HAA5

Why? They’re not powerful enough! The truth is, many of the most popular filters and filtration devices on the market rely on basic technology that regulates as few as 5 of the 320+ dangerous contaminants found in tap water. And HAA5 is one of hundreds of common contaminants they simply are not powerful enough to reduce.

That’s why your best option is to rely on a premium water filter proven to reduce HAA5 and maximize your drinking water quality. 

Get Proven Protection With Clearly Filtered

Our best-selling water pitcher removes up to 99.9% of HAA5 from tap water and well water. In fact, it’s the ONLY water pitcher on the planet that protects you from 365+ contaminants, including HAA5, without targeting beneficial minerals! 

So if you want proven protection from HAA5 and complete confidence in your water, upgrade to Clearly Filtered today to get easy access to the cleanest water!


    • HAA5 is a group of cancer-linked contaminants called haloacetic acids found in tap water in all 50 states.
    • HAA5 has been linked to a variety of short-term health concerns as well as cancer, fetal growth and developmental issues, and liver and kidney problems.
    • HAA5 typically forms when chlorine, and other disinfectants, react with organic matter in water during water treatment / water disinfection process.  
    • The U.S. EPA allows up to 60 parts per billion (60 ppb) of HAA5 in tap water. And HAA5 has been detected in tap water in all 50 states. 
    • Bottled water can contain just as much HAA5 as tap water. Boiling water may actually increase the concentration of HAA5. And the vast majority of mainstream filters are not powerful enough to reduce HAA5.
    • Our best-selling filtered water pitcher removes up to 99.9% of HAA5 from your water, so you can trust every drop.