This week, Westerly households face a key decision about managing PFAS—per- and polyfluoroalkyl substances—in their water: choosing between technology classes for effective treatment.

Why Granular Carbon Beds and Ion-Exchange Resins Are Documented Differently for PFAS

PFAS, also called "forever chemicals," are persistent fluorinated compounds detected at low nanogram per litre (parts per trillion) levels in the Westerly public water system, which draws from groundwater. Two primary treatment approaches documented for residential use are granular activated carbon (GAC) beds and ion-exchange resins.

• Granular Carbon Beds: These use porous carbon material that adsorbs PFAS molecules, especially longer-chain types like PFOA and PFOS. They are effective for a broad range of organics but vary in capacity and lifespan depending on water chemistry and PFAS levels.
• Ion-Exchange Resins: These are specialized polymers designed to exchange ions with PFAS compounds, often targeting specific shorter-chain PFAS less captured by carbon. Their regeneration and maintenance needs differ from GAC.

Documentation separates these technologies because their mechanisms, maintenance, and performance profiles differ, which should influence a household’s choice based on detected PFAS and water characteristics.

The Role of Plumbing Material and Age, Separate From the Source Water

The Westerly Water Department obtains water from groundwater sources, so the source is the primary origin of detected PFAS. However, household plumbing materials and the age of pipes can influence water quality indicators unrelated to PFAS concentrations. Materials like older plastics or metals may affect aesthetics or introduce other elements but do not alter PFAS levels established by source water sampling. It's important to distinguish source contamination from household plumbing effects when considering treatment options.

The Order in Which to Rule Things Out, From Cheapest Check to Laboratory Test

Before selecting between granular carbon and ion-exchange systems, a clear understanding of household water PFAS levels is essential. The recommended approach:

• Start with municipal water quality reports: Westerly Water Department’s EPA public water system record shows detections of PFOA and PFOS above reporting levels but below health-based violations.
• Consult household-specific water tests: Obtain laboratory testing from a certified water analysis lab focusing on PFAS compounds to understand your potable water’s unique profile. These tests clarify which PFAS are present and at what levels.
• Evaluate other water quality factors: Parameters like pH, total dissolved solids, and common secondary contaminants may affect treatment performance and maintenance schedules. These influence the choice and configuration of treatment equipment.

What 'Detected,' 'Median' and 'Range' Mean in the Sampling Record on This Page

Government monitoring in Westerly (2025 UCMR5 data) reports the following for the community water system:

• PFOA was detected in 7 of 14 samples, ranging from just above 0.004 µg/L (4 ng/L) reporting level to a highest result of 0.009 µg/L (9 ng/L), with a median detected value of 0.006 µg/L (6 ng/L).
• PFOS was detected in 5 of 14 samples, with a highest detection of 0.007 µg/L (7 ng/L) and a median of 0.005 µg/L (5 ng/L).
• Other PFAS compounds such as PFHxS, PFNA, and HFPO-DA were not detected above reporting levels.

"Detected" means measurements exceeded the minimum instrument reporting level. The "median" is the middle value of detected concentrations. The "range" indicates variability. These measurements do not indicate violations or unsafe levels—they inform the landscape of fluorinated compounds present in the supply.

Maintenance Rhythm of the Documented Technology in Plain Terms

The documented C-Series PFAS Forever Chemicals Filter, which ships ready to configure, typically requires routine maintenance aligned with the volume of water treated and PFAS loading:

• Filter media replacement: Regular replacement of the granular carbon or resin media is necessary to maintain PFAS reduction efficacy. The timing depends on household water use and detected PFAS levels in the input water.
• Performance monitoring: Periodic testing of treated water helps track when media capacity approaches exhaustion and replacement is due.
• Simple user procedures: Filter housing can be accessed for media change without specialized tools or professional service.

This predictable maintenance rhythm helps households plan for reliable, continuous PFAS reduction.

How the UCMR5 Survey Differs From UCMR3 in Which Compounds It Looked For and at What Level

The UCMR5 survey (2023-2025) monitored a wider array of PFAS compounds in the Westerly Water Department compared to the earlier UCMR3. Key distinctions include:

• Monitoring lower reporting levels for certain compounds, leading to detections in PFOA and PFOS that were less frequently observed previously.
• Expansion of target analytes to include shorter-chain PFAS like PFBS, PFHxA, and PFPeA, which are of growing interest due to their differing environmental behavior and treatment challenges.
• The federal Maximum Contaminant Levels (MCLs) for PFOA and PFOS were updated for 2024, affecting how detections relate to regulatory benchmarks.

The UCMR5 results provide a more detailed profile of fluorinated compounds in public water systems such as Westerly's.

In summary, households in Westerly deciding on PFAS treatment must balance knowledge of source water detections, the distinct properties of granular carbon and ion-exchange resin technologies, and maintenance considerations. Confirming household water PFAS through certified lab testing is essential before selecting the documented C-Series PFAS Forever Chemicals Filter or other systems. This ensures the chosen treatment aligns precisely with the unique profile of fluorinated compounds in use.

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