Synthetic 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.


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

If your water system is a community or non-transient non-community public water system, your water system is required to test for these organic contaminants.  Transient water systems do not have to test for these chemicals.

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, then they can be reduced to sampling once every three years. For systems serving more than 3300 people, they must submit two consecutive quarterly samples every three years for each entry point.  Systems serving less than 3301 are required to submit one sample for each entry point once every three years. This sampling can be eliminated through waivers.

Actions your water system should be taking

  • Complete any sampling for currently regulated Synthetic Organic Contaminants as required.
  • Apply for a “Vulnerability Waiver” if your water system can show that their water supply is not vulnerable to Synthetic Organic Contaminant contamination.
  • Apply for a “Use Waiver” if your water system can show that regulated Synthetic Organic
    Contaminants were not used within a certain radius of your sources. 

If your water system detects a regulated synthetic organic contaminant in your drinking water they must: 

  • Monitor quarterly to show that the contaminant in the drinking water is reliably and consistently below the Maximum Contaminant Level.  Your system then can be reduced to annual monitoring.  
  • After three years of annual monitoring the system can be reduced to once every three years and is eligible for a waiver. 

If the annual average of your water system’s tests indicate levels of a Synthetic Organic Contaminant higher than the maximum contaminant level (MCL), your system is in violation and they must: 

  • Continue quarterly sampling (at times of highest vulnerability, i.e. after fertilizer application and a rain).
  • Notify the Drinking Water Program and complete public notices as required.
  • Work with the Drinking Water Program to determine how Synthetic Organic Contaminants are getting into your water supply.  If possible, eliminate the source of contamination.
  • If treatment is required to remove the Synthetic Organic Contaminants, work with the Drinking Water Program to choose the best available technology for treatment.  Filtering through granular activated carbon is suggested for most Synthetic Organic Contaminants.  Packed tower aeration and polymer addition practices are used for some.
  • Contact resource agencies listed on the Resource Agencies page of this web site for help in planning and finding financing for your system improvements.
  • Change water sources if that is the most economical solution in situations where available.

Maximum Contaminant Level

The Maximum Contaminant Levels for the Synthetic Organic Contaminants are listed below.

Contaminant Maximum Contaminant Level (MCL)
Alachlor  0.002
Aldicarb 0.003
Aldicarb sulfoxide 0.004
Aldicarb sulfone 0.002
Atrazine 0.003
Carbofuran 0.04
Chlordane 0.002
Dibromochloropropane 0.0002
2,4-D 0.07
Ethylene dibromide 0.00005
Heptachlor 0.0004
Heptachlor epoxide 0.0002
Methoxychlor 0.04
Polychlorinated Biphenyls (PCBs) 0.0005
Pentachlorophenol   0.001
Toxaphene 0.003
2,4,5-TP 0.05
Benzo[a]pyrene 0.0002
Dalapon 0.2
Di(2-ethylhexyl)adipate 0.2
Di(2-ethylhexyl)phthalate 0.006
Dinoseb 0.007
Diquat 0.7
Endothall 0.1
Endrin 0.002
Glyphosate 0.7
Hexacholorbenzene 0.001
Hexachlorocyclopentadiene 0.05
Oxamyl (Vydate) 0.2
Picloram 0.5
Simazine  0.004
2,3,7,8-TCDD (Dioxin) 3x10-8

Additional Information

Information on waivers can be found in 40 CFR 141.24(h)(5)