1. Distinguishing UCMR5 from UCMR3: New Compounds and Tighter Detection
The EPA’s Unregulated Contaminant Monitoring Rule 5 (UCMR5) survey, covering 2023 through 2025, has expanded the list of PFAS chemicals tested in Lihue-Kapaa’s public water system compared to the earlier UCMR3. This newer survey includes several additional per- and polyfluoroalkyl substances, such as PFHxS and HFPO-DA, and sets lower reporting thresholds down to parts per trillion levels (nanograms per litre). These changes mean monitoring now captures a wider range of fluorinated compounds at finer detection limits, improving data resolution on the presence of these “forever chemicals.”
2. Different Treatment Media: Granular Carbon Beds versus Ion-Exchange Resins for PFAS
Not all PFAS removal methods perform alike. Granular activated carbon beds and ion-exchange resins represent two documented technologies that treat PFAS in water differently. Carbon filters adsorb multiple PFAS compounds but may vary in capacity depending on the molecular size, while ion-exchange resins can target specific charged PFAS substances with high selectivity. Understanding these mechanisms helps explain why treatment results may differ between equipment types and highlights the importance of selecting a solution documented for the full range of compounds detected by UCMR5.
3. Interpreting Nanograms per Litre and Four Decimal Places in PFAS Measurements
EPA reported PFAS data uses units of nanograms per litre (ng/L), which equals parts per trillion (ppt). Concentrations are listed to four decimal places to accurately present extremely low levels detected—far below health-based MCLs (maximum contaminant levels) established for PFOA and PFOS at 4.0 ng/L. This precision shows many results as "non-detected" above very low reporting levels, reflecting the survey’s sensitivity rather than indicating unsafe water.
4. Plumbing Material and Age Affect PFAS Presence Independently of Source Water
While the public system’s source water in Kauai is surface water, the presence and behavior of PFAS at your tap may also be influenced by your home’s plumbing materials and age. Older plumbing or certain materials can adsorb or leach substances, slightly altering what is detected in tap tests compared to source water. However, the system monitoring data reflects water quality before household plumbing, so individual testing remains necessary to understand your household’s specific conditions after equipment failure.
5. What Changes at the Tap with the Autotrol PFAS Forever Chemicals Filter
Once a documented treatment system like the Autotrol PFAS Forever Chemicals Filter is in place, water delivered to the tap should show significant reductions in per- and polyfluoroalkyl substances. This equipment uses a combination of granular carbon and ion-exchange resin technology designed to capture a broad spectrum of PFAS compounds including those newly monitored under UCMR5. It ships ready to configure and replaces prior equipment to restore treatment capacity after failure.
6. Regional PFAS Sources: Firefighting Foam, Textiles, and Landfills
Common sources of PFAS in water include firefighting foams, textile finishing processes, and landfill leachate. Kauai’s public water record currently shows no detections above reporting levels for these compounds, suggesting these sources have minimal impact on the system’s surface water supply. This regional outcome reduces immediate exposure concerns but does not eliminate the need for household-level treatment when equipment breaks down.
Summary: EPA’s published data for the Lihue-Kapaa system confirms no PFAS detected above reporting levels or federal MCLs in source water, serving about 34,854 people. This record pertains to the public water system only; individual homes should confirm their own water quality, especially after equipment failure. The Autotrol PFAS Forever Chemicals Filter provides a documented way to reduce a wide range of fluorinated compounds at the tap. For detailed data, visit the EPA’s SDWIS public water system records.
Where this information comes from
Source: EPA SDWIS public water system record. Sampled 2024-07-16. These figures describe the public water system's record, not the plumbing inside any individual building.
On record: EPA UCMR5 monitoring (2023-2025) for LIHUE-KAPAA (HI0000400), HI: 360 results across 10 listed contaminants, 0 detections above the reporting level; nothing detected above the method reporting level