What's in Frederick County, VA tap water?
Frederick County sits about 66 miles from our Arlington base and is served primarily by Frederick Water, which provides water to roughly 46,200 people. It draws from the Shenandoah Valley & Blue Ridge karst. The Shenandoah Valley and Blue Ridge run on limestone karst springs and municipal and private wells. That geology, plus valley agriculture, tends to raise nitrate and naturally occurring radionuclides, alongside chlorination byproducts wherever the supply is disinfected.
Find a local installerFrederick Water quality report, explained
What testing of Frederick Water shows for Frederick County, compared with EWG's health guidelines. Being above a guideline is not a legal violation.
Primary water system (EPA)
Frederick Water
Serves about 46,200 people
Contaminants EWG most often flags above its health guidelines for the Shenandoah Valley & Blue Ridge karst:
Larger areas have more than one water system. Enter your exact zip code below for your utility's own EPA record and EWG report.
Measured by the EPA · Frederick County, VA
Frederick County, VA tap water is fully legal.
It is also 13× the health standard for lead.
Frederick County is served by Frederick Water, a surface-water system supplying roughly 46,206 people. It treats its own water rather than buying it from a regional wholesaler, so what comes out of the tap is its work end to end.
Surface water needs heavy disinfection, and chlorine reacting with organic matter in the river is what creates trihalomethanes and haloacetic acids. Those are the contaminants that most often sit above health guidelines here, and they form in the pipes after treatment rather than at the plant.
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 brain and nervous system · EPA limit 10 ppb (action level, lowered from 15 ppb, in force November 2027)
Hormone disruption; harm to fetal growth and child development · no federal limit exists
The EPA's latest round found 1 PFAS compound in this supply. Lead sampling put the ninetieth percentile at 2.5 ppb — meaning nine in ten homes tested below that, and one in ten above it.
Frederick Water, on the EPA's record
- Source
- surface water
- Connections served
- 15,368
- People served
- 46,206
- Violations on file
- 3, none health-based
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 Frederick Water. 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.
12 contaminants above EWG's health guidelines
Everything EWG found above its guideline in Frederick County's water, from testing in 2014-2023. A level can be under the legal limit and still be listed here: EWG's guidelines are set to protect health, not to be easy to meet.
| Contaminant | In this water | EWG guideline | Times over |
|---|---|---|---|
| Haloacetic acids (HAA9) | 28.5 ppb | 0.06 ppb | 475× |
| Total trihalomethanes (TTHMs) | 20.6 ppb | 0.15 ppb | 137× |
| Haloacetic acids (HAA5) | 11.4 ppb | 0.1 ppb | 114× |
| Bromodichloromethane | 4.90 ppb | 0.06 ppb | 82× |
| Trichloroacetic acid | 4.41 ppb | 0.1 ppb | 44× |
| Chloroform | 11.8 ppb | 0.4 ppb | 30× |
| Dichloroacetic acid | 5.93 ppb | 0.2 ppb | 30× |
| Dibromochloromethane | 2.54 ppb | 0.1 ppb | 25× |
| Nitrate and nitrite | 3.41 ppm | 0.14 ppm | 24× |
| Chromium (hexavalent) | 0.147 ppb | 0.02 ppb | 7.3× |
| Dibromoacetic acid | 0.177 ppb | 0.03 ppb | 5.9× |
| Radium, combined (-226 and -228) | 0.16 pCi/L | 0.05 pCi/L | 3.1× |
Source: EWG Tap Water Database, Frederick Water (VA2069250).
The fix for Frederick County water
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Common in U.S. tap water
Frederick County water quality FAQ
Is Frederick County, VA tap water safe to drink?
Public water in Frederick County meets federal EPA legal limits. But "legal" is not the same as "clean": across the Shenandoah Valley & Blue Ridge karst, independent testing routinely finds contaminants like nitrates (agricultural runoff) and radium & radionuclides (naturally occurring) above EWG's stricter health guidelines. Enter your zip code above to see your exact utility's record.
What contaminants are common in Frederick County water?
For the Shenandoah Valley & Blue Ridge karst, the contaminants that most often exceed health guidelines are nitrates (agricultural runoff), radium & radionuclides (naturally occurring), total trihalomethanes (TTHMs), arsenic (naturally occurring, trace) and PFAS (forever chemicals). Your specific levels depend on your utility, which you can look up by zip code above.
Does Sanavia install reverse osmosis systems in Frederick County?
Yes. Frederick County is roughly 66 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'll mail you a free water test kit.
Where does Frederick County tap water come from?
Frederick County's primary public water system is Frederick Water, which serves roughly 46,200 people. It sits in the Shenandoah Valley & Blue Ridge karst, 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 Frederick County tested for these contaminants?
No. Private wells are not covered by municipal testing, so the responsibility falls on the homeowner. If your Frederick 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'll mail you a free water test kit either way.
Contaminants common in the Shenandoah Valley & Blue Ridge karst
Each of these is a plain-English guide to a contaminant class common in Frederick County and the surrounding Shenandoah Valley & Blue Ridge karst — what it is, the health context, and what actually removes it.
Reverse osmosis in Frederick County, VA
Frederick Water treats this water to the federal standard, yet the contaminants listed above still exceed EWG’s stricter health guidelines — Nitrates (agricultural runoff), Radium & radionuclides (naturally occurring), Total trihalomethanes (TTHMs) 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.
PFAS is the reason a carbon pitcher is not enough here. The compounds do not break down, they are measured in parts per trillion, and the federal limit that covers them is not enforceable until 2029. A reverse osmosis membrane is one of the few things at household scale that reduces them rather than passing them through.
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Full testing record for Frederick County · Find a local installer
Detailed city water reports
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