Interpreting a Laboratory Test Report for PFAS in Your Water
Laboratory reports for PFAS (per- and polyfluoroalkyl substances) list concentrations of compounds such as PFOA, PFOS, PFHxS, PFNA, and others, typically measured in nanograms per liter (ng/L), also known as parts per trillion (ppt). For example, federal monitoring in Madison’s public water system has shown no detections of PFOA or PFOS above 0.004 µg/L (4 ng/L), the 2024 federal maximum contaminant levels (MCLs). Other compounds like PFHxS have been detected but well below their federal MCL of 10 ng/L. These figures demonstrate the presence of PFAS at very low levels, but detection does not imply a violation or unsafe condition by itself.
Firefighting Foam, Textile Finishing, and Landfill Sources: Which Fits This Region’s Record
PFAS originate from various sources, including firefighting foams, textile finishing, and landfill leachate. Madison’s water supply, sourced from groundwater, reflects regional environmental impacts. The detection of compounds like PFHxS in limited measurements suggests some influence from these sources, as PFHxS is commonly associated with firefighting foam contamination. However, the overall low concentrations reported indicate limited impact from industrial or landfill sites on the municipal supply serving Madison and surrounding Dane County.
How the UCMR5 Survey Differs from UCMR3 in Analyzing PFAS Compounds
The EPA’s Unregulated Contaminant Monitoring Rule (UCMR) is a program that samples public water systems nationwide to better understand emerging contaminants like PFAS. UCMR5 (2023–2025), covering Madison’s water, includes a wider range of PFAS compounds than UCMR3 (2013–2015) and applies lower reporting levels. For instance, while earlier surveys focused primarily on PFOA and PFOS, UCMR5 adds substances such as PFHxS, PFBA, and HFPO-DA, detecting some of these at low levels that were previously unmonitored. This broader and more sensitive survey provides a deeper picture of PFAS occurrence in the region’s water but does not alone indicate safety concerns.
Household or Facility Symptoms That May and May Not Indicate PFAS Issues
PFAS compounds are chemically stable and typically do not cause immediate effects in water taste, odor, or appearance. Therefore, symptoms like strange smells or discoloration in water are unlikely to be related to PFAS. Instead, concerns about PFAS often arise from awareness of their persistence in the environment, sometimes called "forever chemicals." To understand if your home water is affected, specific PFAS testing is required. General water quality symptoms do not reliably indicate PFAS presence or levels.
How Public-System Records Differ from Private-Well Testing in What They Establish
Public water system sampling, such as the EPA’s monitoring of Madison Water Utility, represents composite data across many connections and sources, offering a regional overview rather than household-specific results. Private well water quality can vary significantly and may require individual testing to determine PFAS levels accurately. Thus, while the public system’s record confirms low regional prevalence of PFAS, it cannot substitute for a private well’s direct analysis if you rely on a private source.
What 'Detected', 'Median', and 'Range' Mean in This Sampling Record
A detection means an instrument measured the compound at or above the laboratory’s reporting level, which for PFAS is often in fractions of micrograms per liter. For example, PFHxS was detected in 4 out of 40 samples with a highest measured value of 0.0073 µg/L (7.3 ng/L) and a median of 0.0057 µg/L (5.7 ng/L). Median indicates the middle value of detected measurements, while range indicates the spread from the lowest to highest detection. These statistical terms describe measurement distribution but do not reflect health risk by themselves.
How the Documented Treatment Technology Removes or Neutralizes PFAS
The C-Series PFAS Forever Chemicals Filter is a water treatment system designed specifically to address PFAS compounds. It works by employing advanced filtration media that capture per- and polyfluoroalkyl substances from water, reducing their concentrations before household use. This technology ships ready to configure with home plumbing setups and offers a documented approach to mitigating "forever chemicals" in residential water supplies, particularly useful when existing equipment no longer effectively controls PFAS.
Summary of Madison Area PFAS Records and Next Steps
Federal monitoring of the Madison Water Utility, serving about 272,000 people in Dane County via groundwater sources, shows low-level detections of some PFAS compounds, all below federal maximum contaminant levels effective in 2024. No results exceed health-based benchmarks, reflecting a water system with regulated control of these substances. For individual households, especially those with prior equipment failure, specific water testing for PFAS is recommended to assess localized conditions. The original public data can be reviewed at the EPA’s Safe Drinking Water Information System (SDWIS) website for this utility.
Where this information comes from
Source: EPA SDWIS public water system record. Sampled 2024-10-08. These figures describe the public water system's record, not the plumbing inside any individual building.
On record: EPA UCMR5 monitoring (2023-2025) for MADISON WATER UTILITY (WI1130224), WI: 400 results across 10 listed contaminants, 6 detections above the reporting level; compared with the applicable federal MCL, none above