What's in Fairfax County, VA tap water?
Fairfax County sits about 9 miles from our Arlington base and is served primarily by Fairfax County Water Authority, which provides water to roughly 1,120,000 people. It draws from the Potomac River watershed. Most of the DC metro area drinks treated Potomac River water. Because that surface water is heavily disinfected to stay safe across a long distribution system, the contaminants that most often exceed EWG's stricter health guidelines here are chlorination byproducts, alongside unregulated contaminants like PFAS and hexavalent chromium.
Find a local installerFairfax Water quality report, explained
What testing of Fairfax Water shows for Fairfax County, compared with EWG's health guidelines. Being above a guideline is not a legal violation.
Primary water system (EPA)
Fairfax County Water Authority
Serves about 1,120,000 people
14
over guideline
"× over" compares the detected level to EWG's stricter health guideline, not the federal legal limit.
Measured by the EPA · Fairfax County, VA
Fairfax County, VA tap water is fully legal.
It is also 82× the health standard for PFOA.
Fairfax County Water Authority runs Fairfax County's water, drawing from surface water and supplying about 1,121,613 people through 281,686 service connections. A system that size runs a long distribution network, and water spends days in it between the plant and the tap.
River water has to be disinfected hard enough to stay safe across the whole network, and this system uses chloramines rather than free chlorine. Chloramine is more stable in long pipe runs and produces fewer trihalomethanes — but it is more corrosive to old plumbing, which is precisely how lead gets into water that left the plant clean.
Every federal limit that applies here is met. Those limits weigh what removal costs. EWG says its health standards are “based only on protecting health and does not consider technical feasibility or the cost of water treatment”. Here is how far apart the two are.
Harm to the immune system; harm to fetal growth and child development; increased cholesterol · EPA limit 4 ppt (set 2024, enforceable from 2029)— also above this
Cardiovascular harm; harm to fetal growth · EPA limit 4 ppt (set 2024, enforceable from 2029)— also above this
Harm to the brain and nervous system · EPA limit 10 ppb (action level, lowered from 15 ppb, in force November 2027)
Harm to fetal growth and child development · no federal limit exists
Harm to fetal growth and child development · no federal limit exists
Harm to fetal growth and child development · no federal limit exists
Hormone disruption; harm to fetal growth and child development · no federal limit exists
Harm to fetal growth and child development · no federal limit exists
PFOA and PFOS were measured above the federal limits too. Compliance is judged on a running annual average rather than a single sample, so this is not a violation — but it is the number EPA itself set as the line.
The EPA's latest round found 8 PFAS compounds in this supply. Lead sampling put the ninetieth percentile at 1.2 ppb — meaning nine in ten homes tested below that, and one in ten above it. It has no violations on file.
Fairfax County Water Authority, on the EPA's record
- Source
- surface water
- Connections served
- 281,686
- People served
- 1,121,613
How this water is treated before it reaches you
Treatment makes water safe to distribute. It is not designed to remove PFAS, and chlorine-based disinfection creates byproducts of its own.
Levels: EPA Fifth Unregulated Contaminant Monitoring Rule (UCMR5, 2023–2025) for PFAS, and the Lead and Copper Rule 90th-percentile result for lead and copper — the highest reported for Fairfax County Water Authority. Health standards: EWG's published drinking water standards, updated February 2025. Levels vary by sampling point and date, and being above a health standard is not a legal violation.
The fix for Fairfax County water
$999$1,250Save $251
or 4 interest-free payments of $249.75 with Shop Pay
Reverse osmosis under your sink, for the 14 contaminants over EWG guidelines in water from Fairfax Water.
Free shipping · 60-day returns · 3-year warranty
What’s really in your tap? Find out in seconds.
Common in U.S. tap water
Fairfax County water quality FAQ
Is Fairfax County, VA tap water safe to drink?
Public water in Fairfax County meets federal EPA legal limits. But "legal" is not the same as "clean": across the Potomac River watershed, independent testing routinely finds contaminants like total trihalomethanes (TTHMs) and haloacetic acids (HAA5) above EWG's stricter health guidelines. Enter your zip code above to see your exact utility's record.
What contaminants are common in Fairfax County water?
For the Potomac River watershed, the contaminants that most often exceed health guidelines are total trihalomethanes (TTHMs), haloacetic acids (HAA5), hexavalent chromium (chromium-6), PFAS (forever chemicals) and lead (from older service lines). Your specific levels depend on your utility, which you can look up by zip code above.
Does Sanavia install reverse osmosis systems in Fairfax County?
Yes. Fairfax County is roughly 9 miles from our Arlington base and inside our service area. A Sanavia Hydra reverse osmosis system installs under your sink and reduces every contaminant class above, and we offer a free in-home water test.
Where does Fairfax County tap water come from?
Fairfax County's primary public water system is Fairfax County Water Authority, which serves roughly 1,120,000 people. It sits in the Potomac River watershed, so its water shares that region's contaminant profile. Larger areas may have more than one utility, so enter your exact zip code above for your own system's EPA record.
Is well water in Fairfax County tested for these contaminants?
No. Private wells are not covered by municipal testing, so the responsibility falls on the homeowner. If your Fairfax County home is on a well, nitrate and naturally occurring contaminants are worth testing for specifically, and a reverse osmosis system reduces them at the tap. We offer a free in-home water test either way.
Is there a water treatment company in Fairfax County, VA?
Yes. Sanavia Water is a water treatment company based in neighboring Arlington: we test your water free at your tap in Fairfax County, VA and install the Hydra reverse osmosis system for $1,250, or $999 if you install it yourself.
Contaminants common in the Potomac River watershed
Each of these is a plain-English guide to a contaminant class common in Fairfax County and the surrounding Potomac River watershed — what it is, the health context, and what actually removes it.
Water treatment company for Fairfax County, VA: reverse osmosis
Fairfax Water treats this water to the federal standard, yet the contaminants listed above still exceed EWG’s stricter health guidelines — Total trihalomethanes (TTHMs), Haloacetic acids (HAA5), Hexavalent chromium (chromium-6) and 2 more. Most of them either pass straight through treatment or form after the plant, in the pipes between it and the tap, which is why the fix has to be at the tap as well.
Lead is the one nothing upstream can fix. It does not arrive from the treatment plant; it comes off the service line and the household plumbing in between, which is why two houses on the same street test differently. A reverse osmosis membrane sits at the end of that run, after every pipe the water has already passed through.
Fit it yourself
$999, under the sink, with the included instructions.
We fit it for you
$1,250 installed in Fairfax County.
Full testing record for Fairfax County · Find a local installer
Further reading for Fairfax County
Detailed city water reports
For the largest DC-metro utilities we publish the full measured contaminant table.
Nearby areas we serve
What's in your Fairfax County tap?
Your water test kit is free.