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Emerging Contaminants

An emerging contaminant is a chemical or material that poses a potential, perceived or real threat to human health or the environment and is a newly found groundwater contaminant or has been found recently with more prevalence. There is typically scarce information available on how often and at what concentrations these contaminants may be present in our environment, and little is generally known about potential health risks that emerging contaminants may pose. Specific federal drinking water standards have not been established for emerging contaminants.

Given the importance and vulnerability of our sole source aquifer, coupled with historic and ongoing threats, the Suffolk County Department of Health Services aggressively conducts monitoring and management of emerging contaminants. The department is continually tailoring programs to investigate and mitigate possible sources of emerging contaminants.

In 2015, Suffolk County laid out a blueprint to address emerging issues in the Comprehensive Water Resource Management Plan. Since then, the Suffolk County Department of Health Services has expanded its own laboratory capability, and is working with the New York State Department of Health’s Wadsworth Laboratory, the New York State Department of Environmental Conservation and their contract laboratories and the Suffolk County Water Authority Laboratory to conduct testing of groundwater and drinking water. Suffolk County has supported the efforts of the New York State Department of Health to establish these new drinking water standards and to evaluate new treatment technologies.

Drinking Water Standards for PFOS, PFOA and 1,4 Dioxane

On August 26, 2020, the New York State Department of Health (NYSDOH) formally adopted drinking water standards for perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA) and 1,4 dioxane. These drinking water standards became effective after public comment, adoption by the New York State Department of Health and publication in the New York State Registry. The new drinking water standards, or Maximum Contaminant Levels (MCLs), are listed below.


  • PFOS: 10 parts per trillion (ppt)
  • PFOA: 10 parts per trillion (ppt)

1,4 Dioxane MCL:

  • 1 part per billion (ppb)

The new MCLs follow the recommendations of the New York State Drinking Water Council (DWQC). On December 18, 2018, the DWQC recommended MCLs for PFOS, PFOA and 1,4 dioxane. The DWQC was established by New York State Public Health Law 1113 for the purpose of providing recommendations to the NYSDOH on emerging contaminants in drinking water.

Additional Information

Notice of Final Adoption of the New York State Drinking Water Standards for PFOS, PFOA and 1,4 Dioxane: (see page 6)

Governor Cuomo July 30, 2020 Press Release:

Proposed Drinking Water Standards: (see page 19) and erratum (see page 13 and Appendix beginning on page 97)

Governor Cuomo July 8, 2019 Press Release:

NYSDOH Drinking Water Quality Council Website:

NYSDOH 2018-12-18 Press Release:

NYSDOH 2018-12-18 Drinking Water Quality Council Recommendations:

Contaminants of Emerging Concern in Suffolk County:

For more information:

Information on Contaminants of Emerging Concern, visit

If you want to view your water quality results and Suffolk County Water Authority is your water supplier, visit

Suffolk County Government

H. Lee Dennison Bldg

100 Veterans Memorial Hwy
P.O. Box 6100
Hauppauge, NY 11788

Riverhead County Center

County Road 51
Riverhead, NY 11901