Public Water Systems and NYS Drinking Water Standards for PFAS and Other Emerging Contaminants

Public Water Systems and NYS Drinking Water Standards for PFAS and Other Emerging Contaminants is available in Adobe Portable Document Format (PDF).

Per- and polyfluoroalkyl substances (PFAS) are contaminants used in many products and have been linked to health issues. New York State has been developing drinking water standards, also called contaminant levels (MCLs) to address these contaminants, starting with the two most common PFAS: perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). Public drinking water with PFOA or PFOS above the MCLs must be treated to reduce the levels below the MCL. Image showing products containing PFAS including furniture, water repellent clothing, furniture, paint and varnish, heat-resistent cookware, pesticides, insulation, food packaging and adhesives

New York’s drinking water standards for emerging contaminants are among the most protective in the country. In 2020, NYS set maximum contaminant levels (MCLs) of 10 parts per trillion (10 ppt) each for perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS), and 1 part per billion (1 ppb) for 1,4-dioxane. New York was the first state to develop an MCL for 1,4-dioxane. New York is working to pass even more drinking water standards and notification levels for up to 23 PFAS.

New York State DOH continues to review the evolving science around health risks associated with drinking water contaminants, closely follow efforts by the U.S. Environmental Protection Agency and other states, and will update or develop additional drinking water standards as needed to protect public health.

About Drinking Water Standards

  • Drinking water standards set maximum contaminant levels (MCLs), that are the highest level of a contaminant allowed in drinking water delivered by public water systems. MCLs are enforceable regulatory limits.
  • All MCLs require public water systems to regularly monitor for contaminants, notify health departments and the public of confirmed exceedances, and work with health departments on a timetable and plan to bring water systems into compliance.
  • MCLs are set at levels that are protective, which means that the risk for health effects if someone drinks water at or below the MCL is minimal. An exceedance of an MCL also does not mean that water is unsafe for use while the public water system takes actions to reduce the levels.
  • MCLs are also set to consider the availability of drinking water treatment technologies, the ability to accurately measure the contaminant, and the cost associated with reducing the contaminant levels below the MCL.
  • MCLs are different then health advisory levels (HALs). HALs, such as EPA’s Interim Health Advisories for PFOA and PFOS, are public health goals that are not enforceable. They do not consider feasibility or the ability for water systems to measure the contaminants at low levels.

Public Water System Requirements

  • Public water systems in New York must monitor for more than 100 different contaminants on a regular schedule, including PFOA, PFOS and 1,4-dioxane.
  • Public water systems must report on all PFAS included in the analytical method when they detect any level of PFOA and PFOS. This helps identify additional unregulated PFAS contaminants that may be present.
  • New York’s largest and some smaller public water supplies must also monitor for a select list of emerging drinking water contaminants every five years under EPA’s Unregulated Contaminant Monitoring Rule.
  • As with all MCLs, water systems must notify their local health department of any exceedances. If there is a confirmed MCL exceedance, the public water system will work with their local health department to notify the public and develop a course of action and timetable to reduce levels below the MCL.
  • Some water systems will need to make significant infrastructure upgrades to their water treatment processes and these projects could take several years to complete. Unless there is an unusual exposure that represents an immediate health risk, the water remains acceptable for use while the water system takes actions to reduce levels below the MCL.

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