Data & Methodology — Fauquier County

Full contaminant data, sample history, and sourcing for Fauquier County. For readers who want to go beyond the summary.

Contaminant Data — All Analytes

381 well testing events on record, covering 28 analytes. Data spans 1945 to 2026.

Contaminant Samples Years Detection Rate Distribution LowModHigh vs. Limit vs. VA Avg
PFOS municipal 39 2023–2025 28%
288% of limit —
PFOA municipal 39 2023–2025 23%
432% of limit —
Manganese 13 1994–2014 54%
4% of limit ↓ 97% below
Arsenic 7 1999–2014 57%
51% of limit ↑ 574% above
Iron 17 1980–2014 59%
5% of limit ↓ 94% below
Radon 9 1994–2014 100%
11% of limit ↓ 87% below
Sulfate 21 1980–2019 100%
3% of limit ↓ 70% below
Uranium 12 1994–2014 42%
3% of limit ↑ 390% above
PFNA municipal 39 2023–2025 5%
48% of limit —
PFHxS municipal 39 2023–2025 23%
38% of limit —
Nitrite 17 1980–2019 47%
0% of limit ↓ 59% below
Nitrate 17 1980–2019 82%
6% of limit ~ typical
Lead 7 1999–2014 43%
2% of limit ~ typical
HFPO-DA (GenX) municipal 39 2023–2025 0%
— —
Fluoride 21 1980–2019 86%
3% of limit ~ typical
Chloride 21 1980–2019 100%
5% of limit ↓ 55% below
Fluoride 21 1980–2019 86%
3% of limit ~ typical
HFPO-DA (GenX) municipal 39 2023–2025 0%
— —
Lead 7 1999–2014 43%
2% of limit ~ typical
Nitrate 17 1980–2019 82%
6% of limit ~ typical
Nitrite 17 1980–2019 47%
0% of limit ↓ 59% below
PFHxS municipal 39 2023–2025 23%
38% of limit —
PFNA municipal 39 2023–2025 5%
48% of limit —
Uranium 12 1994–2014 42%
3% of limit ↑ 390% above
Hardness 21 1980–2019 100%
— ↑ 102% above
PFBS municipal 39 2023–2025 38%
— —
pH 17 1980–2014 100%
— ~ typical
Sodium 21 1980–2019 100%
— ↓ 22% below

Distribution shows the share of samples in each concentration band relative to the EPA Maximum Contaminant Level (MCL): Low = below half the MCL, Moderate = between half and the MCL, High = above the MCL. Analytes without an MCL (e.g. sodium, pH) show — in the limit columns. State average is based on county median values across VA.

Data Coverage & Gaps

Well-sampled analytes (15+ samples)

  • Iron 17 samples
  • Sulfate 21 samples
  • Nitrite 17 samples
  • Nitrate 17 samples
  • Fluoride 21 samples
  • Chloride 21 samples
  • Fluoride 21 samples
  • Nitrate 17 samples
  • Nitrite 17 samples
  • Hardness 21 samples
  • pH 17 samples
  • Sodium 21 samples

Limited data (<15 samples) — interpret with caution

  • Manganese 13 samples
  • Arsenic 7 samples
  • Radon 9 samples
  • Uranium 12 samples
  • Lead 7 samples
  • Lead 7 samples
  • Uranium 12 samples

No private-well PFAS data for Fauquier County

We have no private well sampling data for PFAS compounds (PFOA, PFOS, PFNA, and related chemicals) in Fauquier County. PFAS has been detected in local public water systems (UCMR 5 data) — indicated by the "municipal" badge in the table above — but this does not directly indicate private well contamination. PFAS testing for private wells requires a dedicated lab panel (~$300–$500). If you are near a military base, airport, or industrial site, consider testing proactively. Learn more about PFAS →

Public vs. Private Water in Fauquier County

70 Active public water systems
48,751 Residents on public water

Public water systems in Fauquier County are regulated by the EPA and must test and report contaminant levels. Private well owners are responsible for their own testing — there is no routine monitoring of private wells by any government agency.

CDC Health Outcome Correlations

Where contaminants detected in Fauquier County have established associations with specific health outcomes, we cross-reference CDC PLACES county-level prevalence data. This is a contextual signal, not a causal claim.

Contaminant Associated Condition Fauquier County Prevalence VA Average Source Year
Arsenic Cancer prevalence 7.4% 6.7% 2020
Arsenic Kidney disease rate 2.8% 3.1% 2020

Source: CDC PLACES county-level estimates. Raw data: Download Fauquier County CDC PLACES data →

Data Sources

This report aggregates data from the following public databases:

Methodology

Raw records are downloaded from the Water Quality Portal and normalized to µg/L (ppb). Records are deduplicated by sample ID and date, and certified outliers are excluded. Analyte names are mapped to EPA canonical forms. Detection rates, distribution bands, and MCL comparisons are computed from the normalized dataset.

Distribution bands use the EPA Maximum Contaminant Level as the threshold: concentrations below 50% of the MCL are classed as Low, between 50% and 100% as Moderate, and above 100% as High. For analytes without an MCL (sodium, hardness, pH), distribution is not computed.

State comparison uses the median of county median values across all counties in VA with at least one sample for that analyte.

Last updated: 2026-07-15

Full methodology →