Fleck PFAS Forever Chemicals Filter

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Federal Maximum Contaminant Levels for PFAS Compounds in Rapid City Water

PFOA and PFOS carry new federal MCLs of 4.0 nanograms per litre (parts per trillion) as of 2024

Neither compound was detected above reporting limits in any of 20 system samples.

PFHxS is detected at low levels but remains well below its MCL of 10 nanograms per litre

Two out of 20 samples showed PFHxS slightly above detection thresholds, with maximum detected concentration around 0.0056 micrograms per litre (5.6 nanograms per litre), under the regulatory limit.

Other PFAS including PFNA, HFPO-DA, PFBS, PFHxA, PFPeA, PFBA, and PFHpA were not detected above reporting levels

This suggests a very limited presence or absence of these compounds in the surface water supply serving Rapid City.

Maintenance Rhythm for the Fleck PFAS Forever Chemicals Filter

Filter media replacement is recommended on a routine schedule aligned with household water use

Manufacturers suggest refreshing filtration components to maintain efficacy against PFAS, based on water volume processed rather than calendar time alone.

Periodic backwash cycles keep the system ready, extending effective service life

Backwash functionality regenerates filter media capacity by flushing accumulated particles, ensuring continuous PFAS reduction performance.

Sample Size and Coverage Behind Rapid City PFAS Data

Twenty samples represent monitoring of the public water system that serves over 72,000 people

These samples provide a broad overview of water quality but do not capture household-level variations.

Results reflect system-level data, emphasizing the need for individual well or tap water tests for precise household assessment

Variability in plumbing or localized contamination cannot be detected by system samples alone.

Effect of Source Type and Depth on Detected PFAS Concentrations

Rapid City’s surface water origin typically shows different PFAS profiles compared with groundwater sources

Surface water can be influenced by watershed activities and runoff, whereas wells may reflect soil and aquifer conditions.

Variations in well depth or sample depth affect PFAS detection, thus state or system data are guidance, not household specifics

Deeper sources may have lower PFAS levels; shallower sources are more vulnerable to recent contamination.

Understanding Measurement Units and Precision for PFOA and PFOS

Concentrations are measured in nanograms per litre (ng/L), equivalent to parts per trillion (ppt)

This unit expresses very low substance amounts typical for PFAS analysis.

Four decimal places in reporting indicate high instrument sensitivity and precise quantification

For example, reporting levels as low as 0.004 micrograms per litre means instruments detect quantities as small as four parts per trillion.

Regional PFAS Sources in Pennington County: Firefighting Foam, Textiles, and Landfill Impact

Historical use of aqueous film-forming foam (AFFF) at local airports or military sites is a known regional PFAS contributor

Though no elevated levels were detected in the municipal system, localized impacts can vary.

Textile finishing and landfill leachate are additional possible contributors impacting surface water quality

These sources release fluorinated compounds into the watershed, influencing water treatment challenges.

In summary, Rapid City's public water system data show no PFAS detections exceeding federal MCLs, offering reassurance about general water quality. However, since this record reflects system-level monitoring, households experiencing filter failures should test their own water to understand unique PFAS levels. The Fleck PFAS Forever Chemicals Filter ships ready to configure as a specialized option for homeowners seeking added protection from 'forever chemicals' in their water supply.

Where this information comes from

Source: EPA SDWIS public water system record. Sampled 2025-09-03. These figures describe the public water system's record, not the plumbing inside any individual building.

On record: EPA UCMR5 monitoring (2023-2025) for RAPID CITY (SD4600406), SD: 200 results across 10 listed contaminants, 2 detections above the reporting level; compared with the applicable federal MCL, none above