Water Quality

​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. Some compounds have a health advisory standard which is a suggested limit, but not a regulated limit, under the Clean Water Act.

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 first two testing rounds were full rounds. And then the next three rounds of testing included groups of compounds that had one more of those contaminants detected. We tested the finished water at Franklin and Lee Dukes Water Treatment plants.

The results are very positive, for the few contaminants that we did find in the water, they were at very low levels. We are confident that the quality of your tap water is good.

For those contaminants that we did detect, we will continue to monitor them for any changes in concentration.

Unregulated Contaminants Test Results

 

Contaminant (units)

 

Result

(Highest)

EPA Health Advisory (DWEL used unless otherwise noted)
1,1,1-Trichloro-2-propanone (ppb)1.2 
1,1-Dichloro-2-propanone (ppb)0.8 
Acesulfame-K (ppt)82 
Acetaldehyde (ppb)11 
Boron (ppb)367,000 1
Bromochloroacetonitrile (ppb)0.9 
Chromium, Hexavalent (ppb)0.21 
Deet (ppt)14 
Desethylatrazine (DEA) (ppt)8.5 
Diaminochlorotriazine (DACT) (ppt)35 
Dibromoacetonitrile (ppb)0.9 
Dichloroacetonitrile (ppb)1.2 
Iohexal (ppt)14 
Lincomycin (ppt)10 
Metformin (ppt)7.7 
Metolachlor (ppt)6.8350,0000 1
N-Nitrosodimethylamine (NDMA) (ppt)2.570 2
Perchlorate (ppb)0.1025 3
Perfluorohexanoic acid (PFHxA) (ppt)2.4 
Perfluorooctanesulfonic acid (PFOS) (ppt)2.270 4
Perfluoropentanoic acid (PFPeA) (ppt)2.4 
Quinoline (ppt)13 
Strontium (ppb)3020,000 1
Sucralose (ppt)550 
Tris(2-chloroethyl) phosphate (ppt)12 
Vanadium (ppb)0.67 

Definitions from EPA 2018 Edition of the Drinking Water Standards and Health Advisories Tables:
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 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.

Please note that in the full testing results included below some contaminants tested are currently regulated by the EPA and therefore, have MCLs. However, current EPA approved analytical methods for the contaminants, do not have detection levels as low as those offered by our outside lab. Therefore, these contaminants are considered non-detected by EPA and do not show up on our regular annual reports.

Unregulated Contaminants Monitoring Full Testing Results