Making Your Decision About PFAS in Household Water This Week
If you are wondering whether your home water might contain measurable levels of PFAS, this checklist will help you understand the public water system record for Bexar County and determine your next steps.
1. Differences Between UCMR5 and UCMR3 Monitoring of PFAS
The 2023-2026 UCMR5 survey covers more PFAS compounds than UCMR3 with lower reporting levels
UCMR5 testing by the EPA detects nine individual PFAS substances not all monitored in UCMR3, with reporting levels as low as 0.003 µg/L (nanograms per litre, or parts per trillion). This expanded scope provides a more detailed regional picture of 'forever chemicals' in public water systems.
PFAS compounds like PFOA and PFOS were not detected above reporting levels in San Antonio Water System
The public system serving Bexar County showed no detections above reporting limits for PFOA, PFOS, PFHxS, PFNA, and HFPO-DA. This absence is consistent across 91 samples, reflecting the system’s surface water source and its current treatment and monitoring practices.
2. Why Granular Carbon and Ion-Exchange Resins Are Distinguished in PFAS Treatment
Granular activated carbon filters adsorb many PFAS molecules but vary by compound
Granular carbon beds can reduce a range of PFAS substances, including some longer-chain compounds. However, their effectiveness depends on water chemistry and contact time, and they do not remove all PFAS types equally.
Ion-exchange resins target specific PFAS molecules with different removal mechanisms
Ion-exchange resins can capture charged PFAS compounds that carbon may miss, especially shorter-chain substances. Combining technologies can provide broader coverage for the diverse group of per- and polyfluoroalkyl substances.
3. Interpreting Bexar County’s Median and Range PFAS Measurements for Homeowners
PFBS, PFBA, and PFPeA were occasionally detected at very low concentrations in the public system
Some compounds like PFBS appeared in 2 of 91 samples at levels just above 0.003 µg/L, with medians around 0.0037 µg/L. PFBA showed detections in 3 samples with higher medians but still well below federal limits set for 2024.
None of the detected PFAS in the system exceeded the forthcoming federal maximum contaminant levels
The measurements for all PFAS substances recorded remain below the health-based federal Maximum Contaminant Levels (MCLs) effective 2024, meaning the public water meets current safety standards.
4. How Public Water System Records Differ From Private Well Testing for PFAS
Public system sampling aggregates multiple sources and is not a substitute for home-specific tests
The San Antonio Water System data represents composite testing for large populations, using surface water sources. It does not reveal the condition of tap water at an individual home, where plumbing and local factors can influence PFAS presence.
To know your household’s PFAS levels, a certified laboratory test of your own water is necessary
Only testing water drawn from your tap will establish your specific concentrations of per- and polyfluoroalkyl substances and help identify if household-level treatment is needed.
5. Sample Size and Representativeness of PFAS Data in Bexar County
Ninety-one samples from this system provide a robust regional profile over a multi-year period
This volume of samples allows for observation of occasional low detections but does not necessarily indicate variability at single points of use within Bexar County residences.
Smaller sample sets or private well data require cautious interpretation due to limited scope
Less extensive data sets may not capture the full range of PFAS presence, making careful sampling and retesting essential if concerns arise.
Concluding Summary and Further Information
The EPA’s UCMR5 public water system monitoring for the San Antonio Water System, which serves Bexar County, finds no PFAS concentrations exceeding federal health-based standards. This record covers a large population and uses surface water sources, but does not substitute for individual tap water testing. For households evaluating potential PFAS concerns, testing your water is the key first step. To address PFAS detected at home, the Fleck PFAS Forever Chemicals Filter—a system that ships ready to configure—provides documented technology using granular carbon and ion-exchange resin media to reduce these substances effectively. For detailed public system data, consult the EPA’s official UCMR5 records.
Where this information comes from
Source: EPA SDWIS public water system record. Sampled 2026-06-16. These figures describe the public water system's record, not the plumbing inside any individual building.
On record: EPA UCMR5 monitoring (2023-2025) for SAN ANTONIO WATER SYSTEM (TX0150018), TX: 910 results across 10 listed contaminants, 6 detections above the reporting level; compared with the applicable federal MCL, none above