If you notice concerns about the presence of 'forever chemicals' or PFAS in your household water supply in Hempstead or Lynbrook, you are not alone. New York American Water's Lynbrook public water system serves approximately 220,000 people across about 74,634 connections with groundwater sources in Nassau County. This system is regularly monitored by the Environmental Protection Agency (EPA) under the Unregulated Contaminant Monitoring Rule 5 (UCMR5), which is an ongoing federal occurrence survey that captures measurements of various PFAS compounds but does not itself establish compliance or safety violations.

Differences Between UCMR5 and Previous UCMR3 Surveys

Expanded List of Fluorinated Compounds Monitored

The UCMR5 survey, conducted from April 2023 through July 2025 for Lynbrook's water system, differs from the earlier UCMR3 effort by testing a broader array of PFAS chemicals with improved sensitivity. Specifically, UCMR5 includes compounds such as HFPO-DA and PFBS that were not measured in UCMR3, providing a more comprehensive picture of fluorinated substances potentially present.

Lower Reporting Levels Detect More Trace Amounts

Reporting levels in UCMR5 are generally lower, allowing detection of compounds at smaller concentrations, such as 0.003 to 0.005 micrograms per liter (µg/L) for several PFAS. This means measurements capture even trace presence where before none was reported, improving data resolution for this area's groundwater supply.

Federal Maximum Contaminant Levels (MCLs) for PFAS in This Record

Compounds Now Subject to 2024 Federal MCLs

• PFOA (Perfluorooctanoic acid): No sample exceeded the federal MCL of 4 nanograms per liter (ng/L) or 4 parts per trillion (ppt).
• PFOS (Perfluorooctane sulfonate): One sample measured above the detection threshold but below the federal MCL of 4 ng/L (0.0051 µg/L).
• Other compounds with MCLs: PFHxS and PFNA are monitored with MCLs of 10 ng/L (ppt), while no sample exceeded these thresholds.

Compounds Without Federal MCLs Yet

Some compounds like HFPO-DA, PFBS, PFHxA, PFPeA, PFBA, and PFHpA were detected at or below reporting levels but are not currently subject to federal MCLs under the UCMR5 guidelines.

How Pentair PFAS Forever Chemicals Filter Addresses These Fluorinated Compounds

Removal from Residential Water Supplies

The documented Pentair PFAS Forever Chemicals Filter uses advanced filtration methods specifically designed to reduce concentrations of various PFAS compounds, including PFOA, PFOS, PFHxS, and PFNA, from household water. This system ships ready to configure and provides a direct purchase option to address the typical range of fluorinated substances identified in the Lynbrook water supply.

Effectiveness Against Trace and Median Levels

This treatment technology is capable of lowering PFAS levels well below the range detected in regional government data, improving water quality as delivered at the faucet.

Considerations for Different Household Types

Larger Families or Multiple Bathrooms

Households with more occupants or several bathrooms may require selecting a filter designed with sufficient capacity and flow rate to handle higher daily water use while maintaining effective PFAS reduction.

Second Homes or Seasonal Properties

For properties used intermittently, the decision to treat water for PFAS depends on usage patterns and local water quality variation. Testing the water on-site is recommended to assess the need for treatment during periods of occupancy.

Interpreting the Record’s Median and Range as a Homeowner

Review of the EPA UCMR5 data specific to this system shows the following for detected compounds: PFOS measured up to 0.0051 µg/L, PFHxS up to 0.0063 µg/L, and PFNA at 0.0041 µg/L. These concentrations are well below the 2024 federal MCLs. However, any detection indicates presence, which some homeowners wish to reduce further through filtration. The median detected values indicate that most samples are near or just above the reporting levels, highlighting relatively low but persistent concentrations in the water source.

Changes in Water Quality at the Tap with Pentair Treatment

Once the Pentair PFAS Forever Chemicals Filter is in place, household water experiences substantially lower levels of targeted PFAS compounds. This results in water that meets or surpasses many homeowner goals for reducing exposure to 'forever chemicals'. The taste and clarity of water remain unaffected while reducing fluorinated compounds to levels below those recorded in local government sampling.

All data discussed derive from the EPA SDWIS public water system record for New York American Water - Lynbrook, reflecting groundwater supply conditions for Hempstead (T) and Lynbrook (V) in Nassau County. The full dataset is available from the EPA's official UCMR5 monitoring reports online.

Where this information comes from

Source: EPA SDWIS public water system record. Sampled 2025-07-15. These figures describe the public water system's record, not the plumbing inside any individual building.

On record: EPA UCMR5 monitoring (2023-2025) for NEW YORK AMERICAN WATER - LYNBROOK (NY2902835), NY: 350 results across 10 listed contaminants, 4 detections above the reporting level; 1 results above a 2024 federal MCL