Understanding PFOA and PFOS Units and Detection Levels
Nanograms per litre explained
PFAS compounds like PFOA and PFOS are tracked in water samples at extremely low concentrations, often in the range of nanograms per litre (ng/L), equivalent to parts per trillion. The EPA’s reporting level for these substances is at four decimal places, such as 0.004 µg/L, reflecting the tiny amounts measurable in public water systems.
Implications of four decimal places in measurements
This precision means that detections beneath the reporting level may be undetectable or negligible in impact. For the PEACOCK HILL system serving Pierce County, PFOA and PFOS were not detected above these reporting levels, indicating that the system’s water quality monitoring found no measurable amounts above the federal threshold.
Explaining Hazard Index for Mixtures of Newer PFAS Compounds
What is the hazard index?
The hazard index is a method used to evaluate mixtures of related chemicals, such as newer PFAS compounds found during monitoring. It compares combined levels to reference values without asserting health outcomes. For example, compounds like PFHxS and others detected in Pierce County water were measured but do not constitute a violation or safety breach by themselves.
Current detections and interpretation
Some substances like PFHxS exceeded the EPA’s reporting level but remained below federal maximum contaminant levels (MCLs). This means while these compounds were found at trace levels, they are not flagged as health-based violations in the public water system record.
How the Pentair PFAS Forever Chemicals Filter Addresses PFAS
Filtration technology overview
The Pentair PFAS Forever Chemicals Filter is designed specifically to reduce PFAS levels in household water. It uses targeted media technology to capture and neutralize various fluorinated compounds, including those measured in the Pierce County water system. This filter ships ready to configure for residential use.
Benefits for household water users
By employing this filter, residents can address a broad range of PFAS compounds detected in local groundwater sources, improving water quality regarding these “forever chemicals.”
Differences Between UCMR5 and UCMR3 PFAS Monitoring
Expanded compound list in UCMR5
The latest EPA Unregulated Contaminant Monitoring Rule (UCMR5) includes more PFAS compounds than its predecessor, UCMR3. The 2023-2025 survey conducted on the PEACOCK HILL system tested for additional substances such as PFBA, PFHxA, PFPeA, and others, which were not measured previously.
Lower detection thresholds and more frequent sampling
UCMR5 sampling occurs at more sensitive reporting levels, often with more frequent testing, providing a detailed picture of trace PFAS in public water supplies like those found in Pierce County.
Distinguishing PFAS from Similar Water Quality Concerns
PFAS vs. common taste or odor issues
PFAS are distinct from problems like chlorine taste, sulfur odors, or sediment. They do not cause the staining or hardness issues commonly associated with minerals in water and require specific detection and treatment methods.
Not related to microbial or organic contaminants
Unlike bacteria or organic matter, PFAS represent a class of man-made, persistent fluorinated compounds, sometimes called “forever chemicals” due to their environmental persistence.
Seasonal and Multi-Year Variation in PFAS Levels
Sampling dates and observed ranges
The PEACOCK HILL system’s UCMR5 data covers from February 2024 through October 2024, with multiple measurements showing generally consistent PFAS presence at trace levels, including occasional small peaks in PFHxS and related substances.
Understanding data trends
These variations reflect both natural fluctuations and monitoring sensitivity rather than episodic contamination events, indicating stable but trace levels of these compounds in the groundwater source.
In summary, the public water system record for the PEACOCK HILL system in Pierce County shows no health-based violations related to PFAS compounds as defined by EPA standards. Trace detections at or slightly above reporting levels for certain newer fluorinated compounds do not imply unsafe water. Residents wanting to address these detectable 'forever chemicals' can consider water treatment solutions such as the Pentair PFAS Forever Chemicals Filter. For detailed data, consult the EPA’s Unregulated Contaminant Monitoring Rule database for this system.
Where this information comes from
Source: EPA SDWIS public water system record. Sampled 2024-10-15. These figures describe the public water system's record, not the plumbing inside any individual building.
On record: EPA UCMR5 monitoring (2023-2025) for PEACOCK HILL (WA5366637), WA: 520 results across 10 listed contaminants, 12 detections above the reporting level; 2 results above a 2024 federal MCL