PFAS (Forever Chemicals)
PFAS·Affects liver, kidneys, reproductive, heart
A family of synthetic fluorinated compounds (PFOA, PFOS, PFNA, PFHxS, GenX) that resist degradation, accumulate in the body for years, and are now federally regulated at parts-per-trillion levels.
PFAS
EPA limit
4.0 ppt (PFOA/PFOS, 2024 MCL)
Most at risk
Infants, pregnant women, communities near military bases, airports, and fluorochemical plants
Found in
City water · Well water · Industrial areas
AquaOx filters
YesCoconut shell carbon (whole-house) + RO (recommended pairing for drinking water)
What it does to you
Health effects
PFAS are called "forever chemicals" because the carbon-fluorine bond at their core is one of the strongest in organic chemistry. They do not meaningfully break down in the environment or in the human body. The half-life of PFOA and PFOS in human blood is roughly 2 to 8 years, so even low-level exposure accumulates over time.
The International Agency for Research on Cancer classifies PFOA as Group 1 (carcinogenic to humans) and PFOS as Group 2B (possibly carcinogenic to humans). Documented health effects include elevated cholesterol, liver damage, thyroid disruption, decreased vaccine response in children, pregnancy-induced hypertension and preeclampsia, low birth weight, and kidney and testicular cancer.
The EPA's Maximum Contaminant Level Goal (MCLG) for PFOA and PFOS is zero. The agency concluded there is no level of exposure to these two compounds that is considered fully safe. The enforceable MCLs of 4 parts per trillion were set at the practical limit of what utilities can reliably measure and treat.
Where it comes from
How it gets into your water
PFAS were manufactured in the United States from the 1940s through the mid-2010s for Teflon coatings, Scotchgard, food packaging, firefighting foam (AFFF), and thousands of industrial applications. Although the largest US producers phased out PFOA and PFOS production around 2015, legacy contamination is widespread because the molecules do not degrade.
The most contaminated water systems sit downstream of military bases and airports (where AFFF foam was used in fire training), fluorochemical manufacturing plants, landfills, and wastewater treatment plants that received industrial discharge. PFAS leach from contaminated soil into groundwater and travel for miles in surface water.
Replacement compounds, including GenX (HFPO-DA) and PFBS, were marketed as safer alternatives. They are now also EPA-regulated because subsequent research showed comparable persistence and toxicity.
Fluorochemical plants
DuPont, 3M, Chemours legacy sites
Military bases and airports
AFFF firefighting foam runoff
Wastewater discharge
Industrial effluent into rivers
Biosolid-amended farmland
PFAS-contaminated sewage sludge spread as fertilizer
Find out for yourself
Is it in your water?
As of the April 2024 EPA final rule, all public water systems must complete initial monitoring for the six regulated PFAS by 2027 and meet the MCLs by 2029. Many utilities have already begun publishing results in their Consumer Confidence Report (CCR), and the EPA's UCMR 5 dataset (Unregulated Contaminant Monitoring Rule) makes nationwide system-level data publicly searchable.
Detection is extremely common. EPA's UCMR 5 monitoring has found measurable PFAS in a large fraction of US public water systems tested so far, often at levels above the new MCLs. If your utility has not yet published results, ask them directly when their UCMR 5 sampling is scheduled.
Private well owners near any of the source categories above should test independently through an EPA-certified lab. Standard well tests do not include PFAS; you have to request the EPA Method 537.1 or 533 panel specifically.
The fix
How AquaOx filters it
The AquaOx whole-house system reduces PFAS through its activated coconut shell carbon stage. Carbon adsorbs long-chain PFAS (PFOA, PFOS, PFNA, PFHxS) well, with independent testing on similar GAC systems showing 60 to 90 percent reduction depending on the specific compound and the contact time.
Short-chain PFAS, particularly PFBS and GenX, are harder for carbon to capture. They have smaller molecular footprints and lower affinity for the carbon surface. For these compounds, and for any application where you want to drive PFAS concentrations as close to zero as possible, the gold standard is reverse osmosis.
Our recommendation for PFAS-impacted homes: install The AquaOx for whole-house reduction (carbon also handles the dozens of co-contaminants typical of impacted aquifers) and pair it with the under-sink RO at the kitchen tap for drinking and cooking water. The two stages together filter far more than either alone.