What does the UCMR5 survey tell us about PFAS in Madison’s public water?
The 2023-2025 UCMR5 federal survey assessed several per- and polyfluoroalkyl substances (PFAS), sometimes called 'forever chemicals,' in Madison's public water system, sourced from groundwater. For 40 samples, no PFOA, PFOS, PFNA, HFPO-DA, PFBS, PFHxA, PFPeA, or PFHpA were detected above reporting limits. PFHxS was detected in 4 samples at concentrations well below the 2024 federal maximum contaminant levels (MCLs). PFBA appeared in 2 samples above its reporting level but also remained far below the federal MCL. This detailed sampling provides a broad snapshot of fluorinated compounds in Madison’s municipal water, though it reflects the system as a whole rather than any individual household’s tap water.
How does UCMR5 differ from the earlier UCMR3 survey for PFAS detection?
The UCMR5 program expands the list of monitored PFAS compounds and lowers detection thresholds compared to UCMR3. While UCMR3 focused on fewer PFAS types, UCMR5 includes newer substances such as HFPO-DA and PFBA with lower reporting limits around 0.003 to 0.005 micrograms per liter (µg/L), equivalent to 3 to 5 parts per trillion. This increased sensitivity and compound range help capture a more comprehensive picture of fluorinated compounds' presence in public water systems like Madison’s.
What does the hazard index for mixtures of these fluorinated compounds mean?
The hazard index concept assesses combined exposure risk from multiple PFAS compounds at sub-threshold levels. While Madison’s measurements show no federal MCL exceedances, understanding the cumulative presence of several detected compounds such as PFHxS and PFBA is useful. The index itself does not indicate a health risk by itself but helps guide ongoing monitoring and treatment choices considering the mix and concentrations found.
How do plumbing materials and system age affect PFAS presence in household water?
Plumbing materials and the age of pipes can influence water quality separately from source water content. Certain materials might interact with water or harbor residues, but fluorinated compounds typically originate in source water rather than from plumbing. Therefore, testing household tap water remains essential to determine specific PFAS levels on site, as public system data cannot confirm individual household concentrations.
What is the recommended sequence of testing and checks before choosing treatment equipment?
First, a homeowner should conduct inexpensive checks of plumbing condition and filtration devices in use. Next, collecting a water sample for laboratory analysis specific to the household will establish exact PFAS concentrations because municipal data do not address private plumbing variations. After understanding actual concentrations and household water demand, a proper treatment option can be selected.
How do seasonal and multi-year variations appear in the Madison water record?
The UCMR5 data collection occurs over a multi-year period, capturing measurements from October 2023 through October 2024. Such a time frame accounts for seasonal influences on groundwater quality, allowing fluctuations to be observed and averaged. Madison's data show consistent low-level detections with no upward trends, supporting stability in fluorinated compound levels over time.
Which PFAS compounds now have federal MCLs as of 2024, and which do not?
Starting in 2024, federal MCLs apply to several PFAS compounds: PFOA and PFOS both have an MCL of 4 nanograms per liter (ng/L, equivalent to parts per trillion), while PFHxS, PFNA, and HFPO-DA have higher MCLs set at 10 ng/L. Madison’s results show no detections above these levels. Other monitored compounds like PFBA, PFBS, PFHxA, PFPeA, and PFHpA currently have no federal MCLs, although detections exist at very low concentrations.
To address your household’s specific need for reducing PFAS from your water supply, the C-Series PFAS Forever Chemicals Filter is designed to meet varying daily water demands and reduce multiple fluorinated compounds effectively. This system ships ready to configure based on your measured consumption, making it a practical choice when paired with your water quality analysis.
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