Unregulated Contaminants

Unregulated contaminants or contaminants of emerging concern are compounds for which the EPA has not set a maximum contaminant level (MCL). Some compounds are being studied to better assess how standards for those contaminants can be developed, for example, “forever chemicals.” Some compounds have a health advisory standard which is a suggested limit, but not a regulated limit under the Safe Drinking Water Act (SDWA).

Charlotte Water, working with the EPA and North Carolina Department of Environmental Quality has been testing contaminants of emerging concern or unregulated contaminants.

In addition to participating in the EPA's Unregulated Contaminant Monitoring Rule (results can be found in the Charlotte Water Consumer Confidence reports), Charlotte Water has been working with an outside certified laboratory to analyze drinking water samples for over 740 unregulated compounds.

The majority of the 740 unregulated contaminants Charlotte Water tests for are considered “non detects,” meaning monitoring results did not yield a detectable concentration of that compound, including many PFAS/PFOA “forever chemicals.” They are listed on Consumer Confidence Report.


More about PFAS/PFOA, “Forever Chemicals:” PFAS and PFOA compounds are part of a family of prevalent chemicals that do not break down naturally in the environment, also known as "forever chemicals." The EPA has presented the intent to categorize PFAS/PFOA as regulated contaminants, and therefore establish MCLs (https://www.epa.gov/pfas/pfas-strategic-roadmap-epas-commitments-action-2021-2024). Charlotte Water proactively monitors for 70 per- and poly-fluorinated chemicals and meets or exceeds all drinking water standards. Results from these tests show very low levels of PFAS/PFOA, with most compounds undetectable.

Unregulated Contaminants Test Results

The data presented below is current as of March 1st, 2023 and is an annual summary reflecting the highest result detected during quarterly testing. Pease note the units for each compound are either parts per billion (ppb) or parts per trillion (ppt). Additional EPA Health Advisory levels are noted in the third column, with the legend available below as footnotes.



Unregulated Contaminants Test Results Table

Contaminant (units)

Result (Highest)

EPA Health Advisory
(DWEL used unless otherwise noted)

1H-Benzotriazole (ppt)
Acesulfame-K (ppt)
Boron (ppb)
Bromochloroacetic acid (ppb)
Bromochloroacetonitrile (ppb)
Caffeine (ppt)
Chromium, Hexavalent (ppb)
Dichloroacetonitrile (ppb)
Iodate (ppb)
Iohexal (ppt)
Meprobamate (ppt)
Perchlorate (ppb)
Perfluorohexanoic acid (PFHxA) (ppt)
Perfluorooctanesulfonamide (PFOSA) (ppt)
Perfluorooctanesulfonic acid (PFOS) (ppt)
Perfluorooctanoic acid (PFOA) (ppt)
Perfluoropentanoic acid (PFPeA) (ppt)
Salicylic Acid (ppt)
Strontium (ppb)
Sucralose (ppt)



Definitions from EPA 2018 Edition of the Drinking Water Standards and Health Advisories Tables(PDF, 777KB):
Health Advisory (HA): An estimate of acceptable drinking water levels for a chemical substance based on health effects information; an HA is not a legally enforceable Federal standard, but serves as technical guidance to assist Federal, State, and local officials.
1DWEL: Drinking Water Equivalent Level. A DWEL is a drinking water lifetime exposure level, assuming 100% exposure from that medium, at which adverse, noncarcinogenic health effects would not be expected to occur
2Cancer Group: A qualitative weight-of-evidence judgment as to the likelihood that a chemical may be a carcinogen for humans. Sufficient evidence in animals and inadequate or no evidence in humans.
3Subchronic value for pregnant women.
4Lifetime HA: The concentration of a chemical in drinking water that is not expected to cause any adverse noncarcinogenic effects for a lifetime of exposure, incorporating a drinking water RSC factor of contaminant-specific data or a default of 20% of total exposure from all sources. The Lifetime HA is based on the exposure of a 70-kg adult consuming 2 liters of water per day. For Lifetime HAs developed for drinking water contaminants before the Lifetime HA policy change to develop Lifetime HAs for all drinking water contaminants regardless of carcinogenicity status in this DWSHA update, the Lifetime HA for Group C carcinogens, as indicated by the 1986 Cancer Guidelines, includes an uncertainty adjustment factor of 10 for possible carcinogenicity.