Overview of Westerly's Groundwater-Sourced Water Supply
Westerly, located in Washington County, Rhode Island, receives its public water from a groundwater source managed by the Westerly Water Department. This system serves approximately 35,298 people through 14,800 service connections. Water from the aquifer is treated and distributed to homes and businesses, providing an essential resource for daily use.
UCMR5 Versus UCMR3: Expanding the Fluorinated Compound Survey
The Environmental Protection Agency's Unregulated Contaminant Monitoring Rule (UCMR) has evolved over time. The current round, UCMR5, includes an expanded list of per- and polyfluoroalkyl substances (PFAS), sometimes called "forever chemicals" because of their persistence in the environment. Unlike UCMR3, which covered fewer compounds and different reporting levels, UCMR5 emphasizes detection at lower thresholds and covers additional PFAS species such as PFHxS, PFNA, HFPO-DA, PFBS, PFHxA, PFPeA, PFBA, and PFHpA. These differences mean that the reported data represents a more detailed look at the variety of fluorinated compounds present in the water system.
Interpreting Certified Laboratory Test Reports for PFAS
Certified laboratory reports from municipal monitoring provide results in micrograms per liter (µg/L), nanograms per liter (ng/L), or parts per trillion (ppt), with the measurement unit often expressed as nanograms per liter (1 ng/L equals 1 ppt). For Westerly's water system, PFOA and PFOS detections have been recorded above the reporting limits of 0.004 µg/L, with highest values around 0.009 µg/L for PFOA and 0.007 µg/L for PFOS. Importantly, detections reflect measurements made by analytical instruments but do not indicate health violations or safety concerns. Residents can use certified water testing to ascertain their home's specific water quality and measure concentrations of any PFAS of interest.
Comparing Westerly's PFAS Data with Nearby Washington County Regions
When comparing water quality data within Washington County, it is crucial to consider the number of sampling points and the analytical scope. Westerly's public water system has 14 sampling results per compound during the monitoring interval. Compared to other county systems, variability in reported PFAS is common, influenced by differing groundwater sources and local industrial or environmental factors. However, no health-based violations for PFAS have been recorded for Westerly or the surrounding areas according to EPA records.
Sources of PFAS in Groundwater and Distribution Systems in Westerly
Fluorinated compounds like PFOA and PFOS often originate from historical industrial use, consumer products, firefighting foams, and other activities that result in environmental release. In groundwater-dependent systems such as Westerly's, these compounds can seep from contaminated sites or diffuse through soil into aquifers. Additionally, distribution system materials and practices rarely contribute PFAS. The presence of these substances at low levels reflects regional environmental conditions rather than problems with individual home plumbing or equipment function.
Distinguishing PFAS from Commonly Confused Water Quality Issues
Residents sometimes confuse PFAS with other water quality challenges such as hardness or iron staining. Unlike minerals that cause scale or discoloration, PFAS are synthetic chemicals that do not typically affect water color, taste, or odor directly but raise concern due to their environmental persistence and potential health effects. This differentiation is important when diagnosing water treatment solutions since addressing PFAS requires specific filtration technologies rather than typical water softening or iron removal equipment.
Aesthetic Secondary Standards Versus Health-Based Limits for PFAS in Westerly
It is important to understand that secondary standards address water appearance, taste, and staining potential, whereas health-based maximum contaminant levels (MCLs) reflect risk thresholds. The federal MCLs for PFOA and PFOS, effective as of 2024, are set at 4.0 ng/L (parts per trillion). Some detection results in Westerly have been above the detection limits but these are not violations and do not indicate unsafe water according to the EPA’s records. These distinctions help clarify what the monitoring data means for everyday water use and when treatment might be considered.
The Documented Treatment Technology for Addressing PFAS Post-Equipment Failure
For residents experiencing issues with existing water equipment, the C-Series PFAS Forever Chemicals Filter ships ready to configure for home water treatment. This system is designed specifically to reduce PFAS levels, including PFOA and PFOS, through proven filtration methods matched to federal recommendations. Testing the home’s well or tap water is essential before selecting the appropriate technology to ensure it meets the particular demand figures found on-site.
Where this information comes from
Source: EPA SDWIS public water system record. Sampled 2025-09-02. These figures describe the public water system's record, not the plumbing inside any individual building.
On record: EPA UCMR5 monitoring (2023-2025) for WESTERLY WATER DEPARTMENT (RI1559512), RI: 140 results across 10 listed contaminants, 28 detections above the reporting level; 9 results above a 2024 federal MCL