PFAS “Forever Chemicals”
What is PFAS?
PFAS (per- and polyfluoroalkyl substances) are a family of thousands of synthetic chemicals used in nonstick cookware, waterproof fabrics, food packaging, and firefighting foam. They earn the nickname “forever chemicals” because their fluorine-carbon bonds barely break down, so they persist in the environment and accumulate in the human body.
Health effects
Research has linked PFAS exposure to increased cancer risk, thyroid disruption, elevated cholesterol, reduced immune response, and developmental effects in infants and children. In 2024 the EPA finalized the first national drinking-water limits for several PFAS compounds at just 4 parts per trillion, a signal of how seriously even tiny concentrations are now treated.
In DC-metro tap water
Regional testing, including EWG sampling across Northern Virginia and the wider DC metro, has detected PFAS in local water systems. Standard municipal treatment was never designed to remove them, so what's in the source water often reaches the tap.
How to remove it at the tap
PFAS molecules are small and chemically stable, so they slip past many filters. The two technologies proven to reduce them are high-quality activated carbon and, most effectively, reverse osmosis, whose membrane physically rejects the molecules. A multi-stage RO system like the Sanavia Hydra pairs carbon pre-filtration with an RO membrane for the broadest coverage.
Where PFAS shows up locally
Local water reports where this contaminant class is documented in the utility's data or watershed. Open your area to see the specifics and look up your exact zip code.
Frequently asked
Are PFAS in DC-metro tap water?
Yes. PFAS have been detected across Northern Virginia, DC, and Maryland water systems in regional testing. Levels vary by utility; check your city's report for specifics.
Does reverse osmosis remove PFAS?
Reverse osmosis is independently rated as one of the most effective point-of-use methods for reducing PFAS, because the membrane rejects the molecules rather than just adsorbing them.
Do pitcher filters remove PFAS?
Most basic pitcher filters are not certified for PFAS reduction. Look for reverse osmosis or filters specifically certified to NSF/ANSI 53 or 58 for PFAS.
Related guides
The gap between what's legal and what's healthy
A utility can pass every federal test and still deliver water far above the levels health scientists consider safe. Federal legal limits were largely set decades ago; the health-based guidelines below reflect current cancer- and development-risk research.
No level is considered safe
Sources: EPA National Primary Drinking Water Regulations (legal limits) and the EWG Tap Water Database / state public-health goals (health-based guidelines). A reverse osmosis system reduces every contaminant above at the point of use.