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Emerging Contaminants of Concern in Drinking Water - Tap Score

What Are Contaminants of Emerging Concern in Drinking Water?


Drinking water is constantly monitored and heavily regulated for a variety of water quality attributes, but with more than 80,000 chemicals circulating in our economy (and environment) you may not be too surprised to learn that there are drinking water contaminants we just don’t know much about.[1] The EPA calls such chemicals in drinking water “contaminants of emerging concern.” Contaminants of emerging concern (CECs) have a variety of sources and they can enter our drinking water supplies in a variety of ways.

In this piece, we answer:

  • What are contaminants of emerging concern in drinking water?
  • What challenges do contaminants of emerging concern present?
  • How are these contaminants regulated?
  • How can you protect yourself against contaminants of emerging concern in water?

    What Are Contaminants of Emerging Concern?

    Contaminants of emerging concern are chemicals that are newly detected in water that pose a potential threat to human or environmental health.[2]  We know very little about the impacts of these chemicals and the list continues to grow. Contaminants of emerging concern have many different sources including: pharmaceuticals, personal care products, agricultural chemicals, lawn care products, household cleaning supplies, flame retardants, pesticides, surfactants, and industrial chemicals.

    Only a small fraction of CECs are monitored or regulated. This is largely because they are so new. Some of these contaminants that have been in the hot seat recently are PFAS and GenX, 1,4 dioxane, and pharmaceuticals and personal care products (PPCPs)

    Whether or not they are regulated, CECs can be tested for in any water supply with Tap Score. Popular tests for CECs include:

    1,4 Dioxane Water Test
    1 Analyte Tested
    $ 185.00
    Perchlorate Water Test
    1 Analyte Tested
    $ 205.00
    Tungsten Water Test
    1 Analyte Tested
    $ 149.00

    Difficulty in Researching Contaminants of Emerging Concern

    The truth is, we don’t REALLY know how many and what types of chemicals we interact with in our daily life. Even the EPA’s Chemical Substance Inventory of over 86,000 chemicals is an incomplete list of all chemicals on the market because it excludes chemicals with uses that are not regulated by the Toxic Substance Control Act. [3] [4] That means pesticides, foods, drugs, cosmetics, tobacco, nuclear waste, and munitions are excluded in the over 86,000 chemical inventory because they are regulated by the states. 

    The sheer number of chemicals in existence makes researching contaminants of emerging concern quite difficult. While researchers are hard at work, they are backlogged beyond capacity as they face an ever-expanding list of potential health effects, limited research budgets and of course a limit on time and resources. 

    How Are Contaminants of Emerging Concern Regulated?

    It is safe to say that the EPA has its hands full trying to keep up with regulating each new chemical that poses a threat to our health. The 2022 EPA Contaminant Candidate List (CCL5) included 70+ contaminants that pose a potential risk to human health.[5]

    The contaminants included on this list are not currently subject to national primary drinking water regulations. However, these contaminants are known or anticipated to be present in public water supplies. 

    Each year, the EPA is required to determine whether or not to regulate at least five contaminants from the CCL. This is a lengthy process that requires significant time and energy. 

    This means that most of the contaminants listed on the CCL are not regulated because the regulatory process is so backlogged. Perhaps even more concerning, the CCL is not even close to a complete register of all contaminants of emerging concern. Out of the over 1000 potential contaminants, less than a tenth are listed on the most recent CCL.

    How Do You Test for Contaminants of Emerging Concern?

    Lack of regulation of CECs means that it often falls onto the consumer to test their water for these contaminants. Many labs don’t offer small scale testing for niche compounds (especially since they aren’t required testing for water utilities).

    The good news is that Tap Score enables anyone to test for many contaminants of emerging concern. If you don’t see a test for a chemical you want to know more about, just send Tap Score a message ( and the customer service team will help.

    Health Effects of Contaminants of Emerging Concern in Drinking Water

    We are still learning about the health effects associated with CECs. Some of these chemicals, like 1,4 dioxane, are designated as a “likely human carcinogens,” while others, like phthalates, are considered endocrine disrupting chemicals (EDCs).[6][2] EDCs, which alter the normal function of hormones in our body, can lead to a variety of health effects. What’s more, is that some low-level exposure to contaminants of emerging concern may not show significant effects until later in life.  

    How to Remove Contaminants of Emerging Concern from Drinking Water?

    The scary thing about these contaminants is that they can pass through our water systems largely unmonitored. The truth is, conventional water treatment systems are not always designed to remove such chemicals. Contaminants of emerging concern can vary considerably in chemical structure, health effects, and concentrations which means that a one-off treatment system may not be able to treat all CECs by itself.

    Water treatment methods that are more advanced than those used at a typical drinking water treatment plant, like nanofiltration, reverse osmosis, and membrane bioreactors, have proven potential to remove various CECs from our water supply.

    While these technologies may help address CECs in the water supply, the challenges can be multifaceted. Most utility-scale treatment technologies are very expensive and small utilities in particular may not have the funds to implement the required treatment technology. Perhaps the most pertinent issue is that, because most of these contaminants are unregulated, water treatment facilities are not required to monitor or treat these contaminants so we don’t always know if they are in the water to begin with!

    What’s the Future for Contaminants of Emerging Concern in Drinking Water?

    New chemicals are constantly making their way into our water supply and the water treatment industry has to play catch up. Thankfully, water agencies are aware of these potential risks and many want to begin monitoring and regulating certain contaminants of emerging concern more closely.

    If you are concerned about CECs in your drinking water, Tap Score offers testing options for a host of contaminants of emerging concern that are not currently regulated. For more information, you can contact the Tap Score team of water quality experts, engineers, and chemists at

    Why Trust Tap Score?

    We know how confusing it can be to find advice on water quality and treatment you can trust. That’s part of the reason we made Tap Score—to help improve the way you test and treat your drinking water.

    • No affiliate links: Unlike most sites revolving around water quality, we do not take a cut from sales on filtration systems.

    • Unbiased advice: Our blog is independently researched by our team of water scientists and designed to provide clarity on water quality, not to sell treatment products.

    • Independent laboratory testing: Tap Score test results come from SimpleLab's third-party network of certified laboratories; in other words, accredited labs provide the data without conflicts of interest.

    • Continuously updated:Science never rests. That’s why our content always reflects the latest developments in scientific research and regulatory standards.

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