Federal Sampling Differences: UCMR5 vs UCMR3 for PFAS
Expanded Compound List in UCMR5
The U.S. Environmental Protection Agency's Unregulated Contaminant Monitoring Rule Phase 5 (UCMR5) surveys include more PFAS compounds than the earlier UCMR3. While UCMR3 focused on a smaller selection, UCMR5 monitors ten types of per- and polyfluoroalkyl substances such as PFOA, PFOS, PFHxS, and PFNA at lower detection thresholds.
Lower Reporting Levels Enable Early Detection
UCMR5's reporting levels for compounds range from 0.003 to 0.005 micrograms per liter (µg/L), or 3 to 5 nanograms per liter (ng/L), enabling more sensitive detection of trace fluorinated compounds in public water systems.
Documented Differences in Treatment Materials for PFAS
Granular Activated Carbon (GAC) Beds
Granular carbon beds remove PFAS by adsorbing molecules onto their porous surfaces. Their effectiveness varies by PFAS chain length and operational factors. They provide a physical medium with affinity for many 'forever chemicals'.
Ion-Exchange Resins
Ion-exchange resins remove PFAS through chemical attraction and exchange processes. These resins can target specific PFAS compounds with high affinity, often capturing shorter-chain PFAS less effectively removed by carbon.
What Measurement Terms Mean in the Sampling Record
Detected vs Not Detected
In the UCMR5 data for the WATER AND POWER AUTHORITY-STX system, none of the listed PFAS compounds were detected above their respective reporting levels. "Not detected" means concentrations were below the method detection limits, not that PFAS are absent.
Median and Range in Reporting
Sampling results typically include median values and ranges to summarize data variability. For this system, multiple samples showed consistent nondetect results, indicating low or negligible presence at the time of monitoring.
Identifying Household Symptoms Related to PFAS
Symptoms Not Specific to PFAS
Household indicators such as taste, odor changes or staining are not reliable signs of PFAS presence, as these compounds are colorless and odorless at low concentrations. Detecting PFAS requires laboratory testing.
When to Test Water Specifically for PFAS
If existing equipment for PFAS removal has failed, or if you wish to confirm your water quality, a certified laboratory test targeting the specific PFAS compounds is essential. This is the only way to establish individual household concentrations.
Consequences of Untreated PFAS Over Long Periods
Accumulation Potential
PFAS are known as "forever chemicals" due to their persistence in the environment and resistance to degradation. Without proper treatment, these compounds can accumulate in household water over years.
Health-Based Limits Guide Action
Federal maximum contaminant levels (MCLs) for several PFAS compounds have been set for 2024, serving as benchmarks for safety. Monitoring water quality relative to these MCLs can inform the need for targeted water treatment solutions.
Documented Solution for Homes in the VI Area
For households with previous equipment failure addressing PFAS, the C-Series PFAS Forever Chemicals Filter ships ready to configure and is documented to reduce concentrations of multiple PFAS compounds. Utilizing this technology can support maintaining water quality that aligns with federally recognized benchmarks.
Where this information comes from
Source: EPA SDWIS public water system record. Sampled 2025-08-27. These figures describe the public water system's record, not the plumbing inside any individual building.
On record: EPA UCMR5 monitoring (2023-2025) for WATER AND POWER AUTHORITY-STX (VI0000097), VI: 40 results across 10 listed contaminants, 0 detections above the reporting level; nothing detected above the method reporting level