PFAS

WTR

0.007 ppthealth-based goal (PFOA)

California's own risk scientists put the negligible-risk level for PFOA roughly 570 times below the enforceable federal limit.

Settled science

Stasis Home ResearchEvery claim on this page is graded against peer-reviewed health research and linked to its primary source.Updated 2026-06

PFAS are persistent synthetic chemicals that ride in with the water, not from your pipes. They build up in the body over years, and the health-based goal is effectively zero. The route Stasis can change is your drinking water. A reverse-osmosis filter at the kitchen tap removes more than 94 percent of both legacy and replacement PFAS.

What it is, and where it comes from

PFAS, per- and polyfluoroalkyl substances, are a class of thousands of synthetic chemicals built around the carbon-fluorine bond. That bond does not occur in nature and barely breaks down, which is why they are called forever chemicals. They were engineered for non-stick coatings, stain and water repellents, and firefighting foam. Unlike lead, PFAS does not come from your home's plumbing. It is a source-water contaminant: it enters supplies upstream from industrial discharge and contaminated groundwater, along with firefighting foam at airports and military sites. What the treatment plant delivers is essentially what reaches your tap, so your water source, not your house, sets your risk.

Why it matters

PFAS act on several organ systems through identified biological pathways, and the effects show up at the background blood levels already present in the typical US adult. The clearest signal is on the immune system: in one study of children, doubling the level in their blood tracked with roughly half the antibody response to routine vaccines. The chemicals also push cholesterol up by a few percent and disrupt thyroid hormone, the system tied to energy, weight, and mood. Because PFAS clear from the body over years rather than washing out, ongoing low-level intake builds body burden. The US National Academies put the average American already inside the blood range flagged for potential adverse effects.

IARC, the WHO cancer body, classified PFOA as Group 1, carcinogenic to humans, in 2023, its highest-certainty category, the same as tobacco and asbestos.IARC Monographs Vol. 135: PFOA and PFOS (International Agency for Research on Cancer, WHO, 2023)
In a study of 587 children, doubling the PFAS level in their blood was associated with about half the antibody response to standard childhood vaccines.Grandjean et al., 2012 (JAMA)
Across 73 homes, reverse osmosis and under-sink dual-stage filters removed more than 94 percent of both long-chain and short-chain PFAS; whole-house carbon was widely variable and in some cases raised PFAS in the treated water.Herkert, Merrill, Stapleton et al., 2020 (Environ Sci Technol Lett)
California's health risk agency sets the negligible-risk goal for PFOA at 0.007 parts per trillion, roughly 570 times below the enforceable federal limit of 4 parts per trillion.CA OEHHA Public Health Goal for PFOA and PFOS, 2024

What we grade it against

Where the health research draws the line, versus the legal limit.
Contaminant	Health-based level	Legal limit	Source (health-based)
PFOA (ppt)	0.007negligible-risk goal, kidney cancer endpoint	4.0federal MCL; goal of zero	CA OEHHA Public Health Goal, 2024
PFOS (ppt)	1health-based goal, liver/pancreatic endpoint	4.0federal MCL; goal of zero	CA OEHHA Public Health Goal, 2024
Serum PFAS (ng/mL)	under 2no expected effects; 2 to 20 carries potential for harm	none set	ATSDR / NASEM benchmark guidance

Health-based levels come from peer-reviewed research and government risk scientists working without cost constraints. Legal limits are enforceable compromises. Your report grades to the health column.

What helps

Direct fixes

Reverse osmosis at the kitchen tap (NSF/ANSI 58)
Removes more than 94 percent of both legacy long-chain PFAS and short-chain replacements. The only filter type with consistent performance across the full PFAS range, and the default for any household with detected PFAS or with children.
Covers your drinking water, not the PFAS that enters through food packaging, household dust, or consumer products.
Under-sink carbon block (NSF/ANSI 53)
A reasonable mid-tier choice for low or no detection. Removal is chain-length dependent, roughly 60 to 70 percent for long-chain PFAS.
Carbon is widely variable and weaker on short-chain replacement PFAS, around 40 percent, and in some cases removes nothing. Be honest about the gap before you rely on it.

Bigger retrofits

Whole-house carbon (point-of-entry)
Acceptable only as a supplement to point-of-use filtration, and only with annual breakthrough testing.
Never primary for PFAS. Once the carbon bed saturates it can desorb captured PFAS back into the water, and in some homes raised PFAS above the incoming level. Breakthrough is invisible: no flow drop, no taste change.

Free and behavioral

Scheduled filter replacement
A saturated PFAS filter looks and tastes identical to a working one, so replacement has to run on a schedule, not on symptoms. Carbon cartridges every 12 to 24 months, RO membranes every 2 to 3 years.

We do not claim to remove PFAS from your life. Diet, dust, and consumer products carry it too, and we cannot filter those. What we can do is measure your drinking water, the one route we can actually intervene on, treat it at the tap, and tell you honestly what else is worth changing. The federal limit is moving backward right now. The mechanism that makes PFAS worth filtering has not.

Common questions

Is the PFAS in my water coming from my old pipes?

No. Lead leaches out of old pipes; PFAS does not. It enters your water upstream, before it ever reaches the house, so the contamination is set by your source. That is why a filter at the kitchen tap is the place to intervene.

Didn't the EPA just set PFAS limits? Why still worry?

The first federal enforceable limits were set in April 2024, but in May 2025 the EPA announced it will rescind several of them, with a final rule expected in spring 2026, even though the underlying science did not change. California is moving the other way and tightened its levels in late 2025. We anchor to the mechanism, not the shifting number.

Will a regular carbon pitcher or faucet filter handle PFAS?

Partly, and unreliably. Carbon removes roughly 60 to 70 percent of long-chain PFAS but is much weaker and more variable on short-chain replacements, and in some tests removed nothing. It is better than no filtration for an adult-only household with low detection, but reverse osmosis is the consistent option, especially with children in the home.

How do I know if PFAS is in my water?

A lab test is the only way. PFAS is invisible and tasteless, and it does not leach from your plumbing, so a single grab sample at the kitchen tap is enough, with no special flush timing required. Because levels depend entirely on your source, neighboring homes on different districts can carry very different risk.