Volatile Organic
Contaminants

Synthetic Organic Contaminants (SOCs) are man-made compounds used for a variety of industrial and agricultural purposes.  This group of contaminants includes pesticides, PCBs, and dioxin.  Synthetic Organic Contaminant health effects include damage to the nervous system, kidneys and cancer risks.

Volatile Organic Contaminants (VOCs) are man-made compounds used for a variety of industrial and manufacturing purposes.  Volatile Organic Contaminants are not readily dissolved in water and will tend to separate from the water forming gasses.  Volatile Organic Contaminants have various effects on the liver, kidneys, nervous system and some pose a cancer risk.

Do the Volatile Organic Contaminant regulations apply to my water system?

If your water system is a community or non-transient non-community public water systems, they must test for these contaminants.  Transient non-community water systems such as campgrounds or gas stations are not required to test for Volatile Organic Contaminants in their water supply.

Frequency of Sampling

All community and non-transient non-community systems must test each entry point initially for four consecutive quarters.  If there are no detections, they can be reduced to annual monitoring. Groundwater systems with no detections for three years of annual sampling, can be reduced to once every three years and can qualify for a waiver.  Groundwater systems with a waiver must sample once every six years. Surface water systems must continue annual monitoring unless they get a waiver, then they must monitor once every three years.

Actions your water system should be taking

  • Complete any sampling for the first round of four quarterly samples for currently regulated Volatile Organic Contaminants as required.
  • Apply for a “Groundwater Waiver” or “Surface Water Waiver”.

If the annual average of your water system’s tests indicate levels of a Volatile Organic Contaminant higher than the maximum contaminant level (MCL), your system is in violation of the Maximum Contaminant Level.  Your water system must:

  • Continue quarterly sampling (at times of highest vulnerability).
  • Complete Public Notices as required.
  • Work with the State to determine how Volatile Organic Contaminants are getting into your water supply.  If possible, eliminate the source of contamination.
  • If treatment is required to remove the Volatile Organic Contaminant, choose the best available technology for treatment.  Filtering through Granular Activated Carbon and Packed Tower Aeration are common treatments for most Volatile Organic Contaminant removal.
  • Contact resource agencies listed in the Resource Agencies Section of this pamphlet for help in working out financial needs.Consider changing the source of your water supply as one option.  This may be the most economical solutions when available.
Contaminant Maximum Contaminant Level (mg/l)
Vinyl chloride 0.002
Benzene 0.005
Carbon tetrachloride 0.005
1,2-Dichloroethane 0.005
Trichloroethylene 0.005
para-Dichlorobenzene 0.075
1,1-Dichloroethylene 0.007
1,1,1-Trichloroethane 0.2
cis-1,2-Dichloroethylene 0.07
1,2-Dichloropropane 0.005
Ethylbenzene 0.7
Monochlorobenzene 0.1
o-Dichlorobenzene 0.6
Styrene  0.1
Tetrachloroethylene   0.005
Toluene 1
trans-1,2-Dichloroethylene 0.1
Xylenes (total) 10
Dichloromethane 0.005
1,2,4-Trichlorobenzene 0.07
1,1,2-Trichloroethane  0.005

Additional information

Waiver information can be found at 40 CFR 141.249(f)(7)