If You Want to Know Which PFAS Compounds Have 2024 Federal MCLs in Florence Water
It is often assumed that all detected per- and polyfluoroalkyl substances (PFAS), sometimes called 'forever chemicals,' are regulated the same way. However, as of 2024, only specific fluorinated compounds measured in Florence’s public water system have established federal maximum contaminant levels (MCLs). These MCLs set enforceable limits for water suppliers but are not direct safety declarations for any household.
- PFOA (Perfluorooctanoic acid): has a new federal MCL set at 4.0 nanograms per litre (ng/L) or parts per trillion (ppt). Florence’s system monitoring recorded 3 detections above this level, with a highest value of 5.5 ppt.
- PFOS (Perfluorooctane sulfonate): also has a 4.0 ng/L federal MCL. Florence’s record shows 4 detections exceeding this threshold, with a maximum of 6.7 ppt.
- Other compounds like PFHxS, PFNA, HFPO-DA, PFBS, PFHxA, PFPeA, PFBA, PFHpA: either had no detections above reporting levels or no MCLs currently assigned.
Understanding which compounds have federal limits helps focus treatment choices on addressing regulated risks rather than every detected PFAS.
If You Want to Know What Regional Sources Might Contribute to PFAS in Florence Water
PFAS originate from various industrial and commercial activities. Common sources include firefighting foams used at airports and military sites, textile finishing processes, or landfill leachate.
Florence’s public water system uses surface water and serves a sizeable metropolitan population. The presence of detections for PFOA and PFOS suggests some influence from historic or current regional sources, likely related to urban or industrial activities rather than isolated contamination.
Identifying specific local sources requires environmental investigation, but understanding general regional factors can inform expectations about fluctuations and compound profiles.
If You Notice Variations in PFAS Levels Over Time in Florence’s Monitoring Records
Data collection for Florence spans from November 2024 to September 2025. Over this period, 28 samples were tested for a suite of PFAS compounds. Detected levels for PFOA and PFOS fluctuate slightly above and below reporting thresholds and the federal MCLs.
Such variation is typical due to seasonal changes in source water composition, precipitation patterns, and treatment system dynamics at the municipal level. It does not necessarily reflect changes in your household water without specific sampling.
If You Wonder Why PFOA and PFOS Concentrations Are Expressed in Nanograms per Litre with Four Decimal Places
PFAS compounds like PFOA and PFOS are measured in extremely low concentrations because they are bioaccumulative and persistent. The unit nanograms per litre (ng/L), also known as parts per trillion (ppt), quantifies trillionths of a gram of substance per liter of water.
The four decimal places in detection (e.g., 0.0055 µg/L or 5.5 ng/L) reflect the sensitivity of federal laboratory testing under the Unregulated Contaminant Monitoring Rule (UCMR). These precise measurements help regulators and water systems track even minute amounts of these 'forever chemicals' to determine compliance and manage treatment.
If You Are Preparing to Seek Advice on Treating PFAS in Your Water
Before considering treatment options, you should record these details:
- Your water source type (e.g., municipal surface water supply in Florence).
- Recent laboratory test results for PFOA, PFOS, and other PFAS from a certified independent laboratory specific to your household water.
- The presence or absence of any EPA health-based violations on the public system record (Florence has two health-based violations on record, not necessarily PFAS-related).
- Any current water treatment methods in use in your home.
Having this information will clarify whether treatment targeting PFAS is warranted and assist in evaluating technical solutions.
If You Want to Understand the Sampling Frequency and Sample Size Supporting Florence’s PFAS Data
The Florence City public water system’s PFAS data comes from 28 samples collected between November 2024 and September 2025. These samples represent system-level monitoring, not individual household taps.
Twenty-eight samples provide a snapshot showing some detections above reporting levels for certain PFAS compounds, including PFOA and PFOS. While this is a relatively small sample set, it reflects the systematic federal surveillance design rather than a continuous or comprehensive monitoring of every water source or tap.
Small sample sizes mean results indicate possible presence and trends but cannot fully characterize every home’s water quality.
Conclusion
To resolve if your household water exceeds federal guidance for PFAS, the crucial next step is a certified laboratory test of your own water for PFOA and PFOS concentrations expressed in nanograms per litre. A result below 4.0 ng/L for these compounds indicates compliance with the federal MCL for 2024. If the test shows values above these limits, employing a documented solution such as the C-Series PFAS Forever Chemicals Filter, which ships ready to configure, can effectively reduce PFOA and PFOS levels at your tap.
Where this information comes from
Source: EPA SDWIS public water system record. Sampled 2025-09-15. These figures describe the public water system's record, not the plumbing inside any individual building.
On record: EPA UCMR5 monitoring (2023-2025) for FLORENCE CITY OF (SC2110001) (SC2110001), SC: 280 results across 10 listed contaminants, 18 detections above the reporting level; 7 results above a 2024 federal MCL