What Are PFAS and Why Are They in Drinking Water?
Per- and polyfluoroalkyl substances—PFAS—are a family of more than 14,000 synthetic chemicals characterized by extremely strong carbon-fluorine bonds that do not break down in the environment. This persistence earned them the name “forever chemicals.” They have been manufactured since the 1940s for use in nonstick cookware, waterproof textiles, food packaging, firefighting foam (aqueous film-forming foam, or AFFF), and hundreds of industrial applications.
PFAS enter drinking water supplies through multiple pathways: discharge from manufacturing facilities, leaching from landfills containing PFAS-laden consumer products, runoff from areas where AFFF firefighting foam was used, and application of PFAS-contaminated biosolids to agricultural land. Once in groundwater, PFAS migrate freely because they are highly soluble and resistant to the natural degradation processes that break down most organic contaminants.
The health concerns are well-documented. Epidemiological studies have linked PFAS exposure to increased risk of kidney and testicular cancer, thyroid disease, liver damage, immune system suppression, and developmental effects in children. A 2023 National Academies of Sciences report concluded that blood PFAS concentrations above 2 nanograms per milliliter are associated with clinically meaningful increases in cancer risk, while concentrations above 10 ng/mL substantially elevate risks for multiple health endpoints.
What Did the Original 2024 EPA PFAS Rule Require?
In April 2024, the EPA finalized the first-ever enforceable national drinking water standards for PFAS under the Safe Drinking Water Act. The rule established legally binding Maximum Contaminant Levels for six individual PFAS compounds and a hazard index for PFAS mixtures:
| PFAS Compound | MCL (2024 Final Rule) | 2026 Revision Status |
|---|---|---|
| PFOA (perfluorooctanoic acid) | 4 ppt | Retained |
| PFOS (perfluorooctane sulfonic acid) | 4 ppt | Retained |
| PFHxS (perfluorohexane sulfonic acid) | 10 ppt | Rescinded |
| PFNA (perfluorononanoic acid) | 10 ppt | Rescinded |
| PFBS (perfluorobutane sulfonic acid) | Hazard Index = 1 | Rescinded |
| GenX (HFPO-DA) | 10 ppt | Rescinded |
The original compliance timeline required public water systems to complete initial monitoring by 2027 and achieve full compliance with MCLs by 2029.
What Changed in the 2026 EPA PFAS Rule Revisions?
The 2026 revisions represent a significant narrowing of the original rule’s scope. Under the revised framework:
PFOA and PFOS MCLs Remain at 4 ppt
The enforceable limits for the two most widely studied and most frequently detected PFAS compounds are unchanged. PFOA and PFOS are the “legacy” long-chain PFAS that were the primary constituents of 3M’s Scotchgard and DuPont’s Teflon manufacturing processes. They are also the dominant PFAS compounds found in AFFF firefighting foam contamination plumes.
Four Additional PFAS MCLs Rescinded
The MCLs for PFHxS, PFNA, PFBS (as part of the hazard index), and GenX (HFPO-DA) have been rescinded. The stated rationale centers on concerns about the scientific basis for setting enforceable limits at the levels specified in the original rule, as well as cost-benefit considerations for water systems. This does not mean these compounds are safe—it means the federal government has elected not to regulate them with enforceable limits at this time.
Compliance Deadline Extended to 2031
The deadline for public water systems to achieve compliance with the remaining PFOA and PFOS MCLs has been pushed from 2029 to 2031. Monitoring requirements have also been adjusted, with initial monitoring now expected to begin by 2028.
What the Revisions Do Not Change
Several important elements remain in force. The MCL Goals (MCLGs) for PFOA and PFOS remain at zero, reflecting the EPA’s assessment that no level of exposure is without risk. State-level PFAS regulations, which in many cases are more stringent than federal rules, are unaffected by the federal revisions. States including Michigan, New Jersey, Vermont, Massachusetts, and New Hampshire have their own enforceable PFAS standards that continue to apply.
How Does PFAS Contamination Affect Utah?
Utah’s PFAS contamination landscape is closely tied to military activity. Hill Air Force Base, located in Davis and Weber Counties just north of Salt Lake City, has been a significant source of PFAS groundwater contamination due to decades of AFFF firefighting foam use during training exercises and emergency response operations. The Department of Defense has identified multiple contamination plumes in the vicinity of the base, with PFOA and PFOS concentrations in some monitoring wells exceeding 10,000 ppt—more than 2,500 times the EPA’s MCL.
The Utah Department of Environmental Quality (UDEQ) has conducted sampling at additional locations across the state, including airports, fire training facilities, and industrial sites where AFFF was historically used. Contamination has been confirmed at several locations along the Wasatch Front, including areas in Davis County, Weber County, and Salt Lake County.
For commercial and industrial facilities drawing groundwater in affected areas, PFAS is not a theoretical concern. Even facilities using municipal water may be affected, as some smaller public water systems source from wells that intersect PFAS plumes. The extended compliance deadline to 2031 gives water utilities additional time, but it does not change the fundamental reality that PFAS-contaminated water will eventually need to be treated.
How Does Reverse Osmosis Remove PFAS from Water?
Reverse osmosis is the most effective commercially proven technology for removing PFAS from drinking water and process water. RO membranes operate by forcing water through a semi-permeable barrier with pore sizes in the range of 0.0001 microns (0.1 nanometers). PFAS molecules, even the smaller short-chain varieties, are significantly larger than these pores and are rejected at very high rates.
Published research and field testing data consistently demonstrate the following PFAS rejection rates for properly designed RO systems:
| PFAS Compound | Chain Length | RO Rejection Rate |
|---|---|---|
| PFOA | 8 carbons (long-chain) | 99%+ |
| PFOS | 8 carbons (long-chain) | 99%+ |
| PFHxS | 6 carbons (short-chain) | 96-99% |
| PFNA | 9 carbons (long-chain) | 99%+ |
| PFBS | 4 carbons (short-chain) | 95-98% |
| GenX (HFPO-DA) | Short-chain ether | 96-99% |
The key advantage of RO over granular activated carbon (GAC) and ion exchange—the other two EPA-recognized treatment technologies for PFAS—is that RO removes all PFAS compounds simultaneously, including the shorter-chain varieties that break through GAC beds relatively quickly. GAC is effective for long-chain PFAS like PFOA and PFOS but requires frequent media replacement when short-chain PFAS are present. Ion exchange resins are more effective than GAC for short-chain PFAS but are significantly more expensive to regenerate or replace.
What Should Commercial Water Users Do Now?
Even with the narrowed federal rule and extended timeline, the direction of PFAS regulation is clear: stricter limits over time, broader compound coverage at the state level, and increasing public awareness driving market expectations beyond regulatory minimums. For commercial and industrial water users, particularly those in areas with known PFAS contamination, a proactive approach makes both regulatory and business sense.
Step 1: Test Your Water
If you have not tested your water supply for PFAS, do so now. EPA Method 533 and Method 537.1 can detect PFAS at low-ppt levels. Testing costs $200-$500 per sample through certified commercial laboratories. Test both your source water and your finished water if you have existing treatment in place.
Step 2: Evaluate Your Exposure
Determine whether your facility is located near known PFAS contamination sources: military installations, airports, fire training areas, or industrial facilities that historically used PFAS-containing products. The UDEQ maintains a public database of known PFAS contamination sites in Utah.
Step 3: Plan for Treatment
If PFAS is detected above 4 ppt for PFOA or PFOS in your water supply, treatment will eventually be required whether by federal mandate or market expectation. Commercial RO systems designed for PFAS removal can be sized and installed for facilities ranging from small commercial buildings to large industrial complexes. AMPAC Water Systems, based in Woods Cross, UT, provides full engineering support from water quality analysis through system design, installation, and ongoing maintenance.
Step 4: Consider Multi-Contaminant Treatment
One of the advantages of RO-based treatment is that it removes far more than just PFAS. A system installed for PFAS compliance will also reduce TDS, heavy metals, nitrates, microplastics, and other emerging contaminants. This multi-contaminant capability often improves the economic justification for treatment by addressing several water quality concerns simultaneously.
For more information on the full range of contaminants that reverse osmosis removes, see our detailed guide: How Reverse Osmosis Removes PFAS, Microplastics, and More.
To discuss PFAS treatment options for your specific application, contact AMPAC Water Systems for a consultation.