PFAS in San Antonio Water: What the 2026 Test Results Show

Does San Antonio water have PFAS?

Based on testing conducted by San Antonio Water System and reported through the EPA's Unregulated Contaminant Monitoring Rule (UCMR5), PFAS have not been detected at levels above the EPA's April 2024 maximum contaminant levels in the SAWS main system. SAWS tested 16 to 18 production wells across its service area. Only one well, in Castle Hills, returned any detectable PFAS reading, and that result was at the detection threshold and below the new MCL. A subsequent test of the same well showed no detectable PFAS.

The Edwards Aquifer's protected recharge zone and its deep limestone filtration pathway contribute to its relatively low vulnerability to PFAS compared to surface water systems and shallow aquifers near industrial areas. PFAS are most commonly associated with industrial manufacturing, military fire training areas, and biosolids-amended agricultural land. The Edwards recharge zone is a designated protected area under Texas law, which limits the type of land use activity above it.

That said, the EPA's PFAS MCL rule is newly enforceable as of 2026, and SAWS, like all large water systems, is in the ongoing compliance monitoring period. The landscape may change as more comprehensive testing occurs. For current and updated PFAS monitoring results, consult the SAWS water quality report directly at saws.org/your-water/water-quality/water-quality-report. The Axios San Antonio reporting from 2024 on the SAWS PFAS testing program is a useful reference for the public record of these findings.

Want to understand the full picture of what is in San Antonio water? Read our guide to San Antonio water quality and the SAWS 2026 water quality report breakdown.

What PFAS were found in San Antonio tap water?

UCMR5 monitoring data for the SAWS service area shows only PFBS (perfluorobutane sulfonic acid) at trace levels in limited sampling locations. PFBS is a shorter-chain PFAS compound; the EPA's April 2024 MCL rule focuses primarily on PFOA, PFOS, PFNA, PFHxS, HFPO-DA (GenX Chemicals), and PFBS in a mixture calculation.

PFOA and PFOS, the two compounds with the most extensive health research and the strictest 4 ppt individual MCLs under the new rule, were not detected above threshold levels in the SAWS system.

It is important to apply accurate context here. San Antonio's PFAS profile is among the most favorable of any large U.S. city due to the Edwards Aquifer's natural filtration and protected recharge zone. Cities drawing from surface water sources near industrial corridors or former military bases have significantly higher PFAS burdens. Verify any numbers cited here with the current SAWS CCR and UCMR5 reporting before drawing conclusions, as this is a rapidly evolving regulatory area.

What is the EPA limit for PFAS in drinking water?

The EPA finalized its PFAS National Primary Drinking Water Regulation in April 2024, the first federal enforceable limit on PFAS in drinking water. The rule sets maximum contaminant levels (MCLs) for six PFAS compounds. PFOA and PFOS each have individual MCLs of 4 parts per trillion. PFNA and PFHxS each have individual MCLs of 10 parts per trillion. HFPO-DA (GenX) has an MCL of 10 parts per trillion. PFBS is regulated under a hazard index mixture formula rather than a standalone MCL.

Public water systems serving more than 10,000 people, including SAWS, were required to begin monitoring under the new rule and must notify the public of detections above the MCLs. Systems have until April 2029 to install treatment to achieve compliance if violations are detected.

For context: 4 parts per trillion is an extremely low concentration. One part per trillion is equivalent to one drop of water in 20 Olympic-size swimming pools. The health basis for these limits comes from evidence linking chronic PFAS exposure to increased risks for certain cancers, thyroid dysfunction, and immune system effects, particularly at longer-chain compound exposures over many years. The EPA's decision to set limits at 4 ppt for PFOA and PFOS reflects a precautionary approach given the persistence of these compounds and the accumulated health literature. Consult the EPA's PFAS resources at epa.gov/pfas for the full regulatory record.

How do you remove PFAS from drinking water?

The EPA and the National Sanitation Foundation identify three treatment technologies as effective for PFAS removal at the point of use: reverse osmosis (RO), activated carbon (particularly granular activated carbon, or GAC), and anion exchange resins. For residential use, under-sink reverse osmosis systems certified to NSF/ANSI Standard 58 for PFAS reduction are the most accessible and cost-effective option.

An under-sink RO system removes PFAS by forcing water through a semi-permeable membrane that blocks contaminants at the molecular level. Systems certified under NSF P473 (which covers PFOA and PFOS removal) or NSF 58 with PFAS claims typically achieve greater than 90 percent removal of targeted PFAS compounds.

Activated carbon filters, including high-quality pitcher filters and under-sink carbon block units, can reduce PFAS at lower concentrations but are less consistently effective than RO membranes. For San Antonio's very low PFAS burden, a quality carbon filter may provide adequate additional protection. For households with infants, pregnant individuals, or immunocompromised members who want maximum protection, a certified RO system is the more reliable choice.

Whole home filtration systems using GAC can reduce PFAS in all household water, including showers, but are significantly more expensive to install and maintain than point-of-use RO systems. Given San Antonio's low baseline PFAS levels, a whole-home PFAS treatment system is rarely warranted based on current data.

For San Antonio homeowners primarily concerned about hard water, the good news is that a reverse osmosis system under the kitchen sink addresses both hard water minerals in drinking water and provides an extra margin of PFAS protection. Pairing an RO system with a whole home water softener is the most comprehensive approach. Learn more in our guide comparing water softeners vs water filters for San Antonio water.

Is San Antonio tap water safe to drink in 2026?

Yes. San Antonio tap water meets all EPA Safe Drinking Water Act standards as of the 2024 Consumer Confidence Report, with no MCL violations for regulated contaminants. SAWS operates one of the larger compliant municipal water systems in Texas, and its treatment processes are audited by the TCEQ and EPA.

The Environmental Working Group (EWG), a nonprofit that applies stricter non-regulatory health guidelines, identifies 15 contaminants in San Antonio water that exceed its own guideline levels, primarily disinfection byproducts (trihalomethanes and haloacetic acids) and chromium-6. All of these are within federal legal limits. The EWG guidelines are precautionary thresholds rather than enforceable MCLs. Consult the EWG Tap Water Database for the full San Antonio dataset.

For the majority of San Antonio residents, tap water is safe for drinking. Homeowners who want additional peace of mind, particularly for infant formula preparation or for households with specific health vulnerabilities, can add an under-sink RO system to address both hard water minerals and any residual disinfection byproducts in drinking and cooking water.

Schedule a free in-home water test with True H2O at (210) 726-6895. We test your specific tap water for hardness, chlorine, pH, and total dissolved solids, and explain what the results mean for your family. No cost, no obligation.

Should San Antonio homeowners filter their water for PFAS?

Based on current data, San Antonio's PFAS levels in the SAWS main system do not require remediation from a public health standpoint. The levels detected are below the EPA's April 2024 MCLs, and the Edwards Aquifer's geology provides natural barriers to many common PFAS pathways.

However, homeowners who want a precautionary approach have a straightforward option: a certified under-sink reverse osmosis system serves both purposes in San Antonio. It removes the hard water minerals that are the primary water quality concern for most residents and provides greater than 90 percent reduction of PFAS compounds simultaneously. The cost of an RO system for a single-point installation at the kitchen sink typically runs 200 to 600 dollars for equipment plus installation.

The decision to add point-of-use filtration for PFAS is a personal one based on risk tolerance, household composition, and budget. The available science suggests that the current San Antonio PFAS profile does not represent an acute risk. That assessment may shift as monitoring data accumulates under the new EPA rule over the next two to three years. Staying current with SAWS annual water quality reports and EPA PFAS monitoring updates is the most practical action for informed homeowners.

For the full picture of what is in San Antonio water and the treatment options that make sense for this specific water profile, read our San Antonio water quality guide or call True H2O at (210) 726-6895.