Water Quality

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Unlike many areas of the country, Monroe County has more than enough water to satisfy current and future needs. Our water source, Lake Ontario, and the other Great Lakes contain 20% of the world’s fresh water!

EPA National Primary Drinking Water Regulation for PFAS


Public health protection is our highest priority. The Monroe County Water Authority provides drinking water that is safe, high quality, and in compliance with all federal and state water quality regulatory standards. On April 10, 2024, the US Environmental Protection Agency (EPA) announced the final National Primary Drinking Water Regulation (NPDWR) for six concentrations of man-made chemicals called per- and polyfluoroalkyl substances, or PFAS, in drinking water. The EPA regulates the safe levels of more than 100 compounds in drinking water under the requirements of the federal Safe Drinking Water Act.

What are PFAS?

PFAS are a category of manufactured chemicals that have been widely used in industrial and consumer products since the 1940s. Examples include carpets, clothing, textiles, food packaging, firefighting compounds, and many other modern industrial products. There are thousands of different PFAS compounds, some of which have been more widely used and studied than others. The EPA says some of these chemicals can cause serious health problems if you are exposed to them over a long period of time, or at certain critical life stages like pregnancy and early childhood. Most people are exposed to these chemicals through consumer products. Drinking water can be an additional source of exposure in communities where these chemicals have entered the water supplies. In many areas of the country, PFAS compounds are considered to be ubiquitous in the environment. PFAS chemicals tend to break down slowly in the environment and can build up in people, animals, and the environment over time.

What is the new rule?

In this final rule, EPA set limits, known as maximum contaminate levels (MCLs), for the concentrations of five individual PFAS compounds and one mixture of two or more PFAS compounds. This mixture includes a group of four PFAS compounds and is called a Hazard Index, or HI. The Hazard Index is an approach that EPA uses to understand health risks from exposure to a chemical mixture. The HI is a sum of fractions where each fraction compares the level of each PFAS measured in the water to a health-based water concentration. MCLs are the highest level for a contaminant allowed in drinking water. MCLs are set as close to maximum contaminant level goals as feasible using the best available treatment technology while taking cost of removal into consideration. MCLs are enforceable drinking water standards. The PFAS chemicals and MCLs for this new rule are listed below.

PFAS ChemicalMaximum Contaminant Level (MCL)
PFOA4 ppt
PFOS4 ppt
PFNA10 ppt
PFHxS10 ppt
HFPO-DA  (GenX chemicals)10 ppt
Hazard Index1
Hazard Index = Mixture of two or more compounds from a group of PFAS that includes PFNA, PFHxS, HFPO-DA, and PFBS.  The Hazard Index is a unitless summation of fractions.
ppt = Parts Per Trillion

What does the rule require for public water systems?

  • Within three years (by 2027):
    • Complete initial PFAS monitoring or obtain approval to use previously collected monitoring data.
  • At three years (Starting 2027):
    • Start routine compliance monitoring.
    • Provide results data for PFAS monitoring in Annual Water Quality Reports.
    • Start issuing public notification for any monitoring and testing procedure violations.
  • At five years (Starting 2029):
    • Comply with the PFAS maximum contaminant levels.
    • Provide public notification for violations of the PFAS maximum contaminant levels.

Are there state regulations for concentrations of PFAS in drinking water?

Yes. On August 20, 2020, New York revised state Public Health Law and adopted new drinking water standards for public water systems that set maximum contaminants levels (MCLs) of 10 ppt for concentrations of PFOA and PFOS. The standards require public water systems to routinely monitor for PFOA and PFOS, notify health departments and the public of confirmed exceedances, and work with health departments on a compliance timetable and plan to reduce the concentration levels of these chemicals below the MCL.

Over the next two years, New York State will have to adopt requirements and apply for approval (known as primacy) to oversee implementation of the PFAS NPDWR. New York must ensure that state regulations are no less stringent than the regulations promulgated by the EPA.

What are the PFAS levels in MCWA’s drinking water?

The Monroe County Water Authority performs quarterly water quality testing for PFAS compounds on our source waters, treated drinking water leaving our water treatment plants, and at entry points to our distribution system for water we purchase from the city of Rochester and Erie County Water Authority. All of MCWA’s water has tested below federal and state regulatory levels for measured PFAS compounds. Summaries of these and all our water quality testing results we submit for compliance with federal and state water quality regulations can be viewed here.

What is MCWA doing about PFAS in drinking water?

The drinking water we supply remains in compliance with federal and state water quality standards and regulations. We recognize concentrations of PFAS compounds in drinking water is an important concern for customers. That is why more research and investment is needed. Specifically, we seek to:

  • Continue robust testing and monitoring for levels of PFAS in our water.
  • Develop understanding of other established and emerging treatment options.
  • Develop practical and feasible strategies to reduce levels of PFAS where and when testing shows concentrations above regulatory standards.

Again, public health and the quality of your drinking water is our top priority.


  • For questions about specific health concerns, talk to your health care provider who is most familiar with your health history and can provide advice and assistance about understanding how drinking water may affect your personal health.
  • For questions about levels of contaminants in our water supply, our regulatory compliance monitoring program, water treatment processes, or general questions, contact Customer Service at 442-7200.
  • For more information about drinking water regulations, health advisories, or advice about your drinking water, contact your local health department:
    • Monroe County Residents: Monroe County Department of Public Health 753-5057.
    • Orleans County Residents: Orleans County Department of Health 589-3278.
    • Genesee County Residents: Genesee County Department of Health 344-2580 ext. 5555.
    • Wyoming County Residents: Wyoming County Department of Health 786-8894.
    • Livingston County Residents: Livingston County Department of Health 243-7280.
    • Ontario County Residents: NYSDOH, Geneva District Office (315) 789-3030.
    • Wayne County Residents: NYSDOH, Geneva District Office (315) 789-3030.

References and Resources:

EPA – Final PFAS National Primary Drinking Water Regulation

NYSDOH – Public Water Systems and Drinking Water Standards for PFS & Other Emerging Contaminants

NYSDOH – Drinking Water Protection Program