Data & Methodology — Stafford County Well Water

Contaminant Data — All Analytes

303 well testing events on record, covering 20 analytes. Data spans 1951 to 2026.

Contaminant	Samples	Years	Detection Rate	vs. Limit	vs. VA Avg
PFOS municipal	8	2024–2025	50%	132% of limit	~ typical
Manganese	5	1994–2015	100%	27% of limit	↓ 79% below
Iron	6	1974–2015	83%	2% of limit	↓ 98% below
Arsenic	3	2003–2015	33%	1% of limit	↓ 63% below
Chloride	7	1974–2026	100%	4% of limit	~ typical
Fluoride	7	1974–2026	86%	1% of limit	↓ 85% below
HFPO-DA (GenX) municipal	8	2024–2025	0%	—	—
Lead	3	2003–2015	33%	1% of limit	~ typical
Nitrate	6	1974–2026	67%	3% of limit	~ typical
Nitrite	5	1994–2026	40%	0% of limit	↓ 68% below
PFHxS municipal	8	2024–2025	12%	30% of limit	~ typical
PFNA municipal	8	2024–2025	0%	—	—
PFOA municipal	8	2024–2025	0%	—	—
Radon	1	1994	100%	6% of limit	↓ 53% below
Sulfate	7	1974–2026	100%	8% of limit	↑ 23% above
Uranium	4	1994–2015	75%	1% of limit	~ typical
Hardness	7	1974–2026	100%	—	↑ 57% above
PFBS municipal	8	2024–2025	0%	—	—
pH	5	1994–2015	100%	—	~ typical
Sodium	7	1974–2026	100%	—	~ typical

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

Limited data (<15 samples) — interpret with caution

Manganese 5 samples
Iron 6 samples
Arsenic 3 samples
Chloride 7 samples
Fluoride 7 samples
Lead 3 samples
Nitrate 6 samples
Nitrite 5 samples
Radon 1 sample
Sulfate 7 samples
Uranium 4 samples
Hardness 7 samples
pH 5 samples
Sodium 7 samples

No private-well PFAS data for Stafford County

We have no private well sampling data for PFAS compounds (PFOA, PFOS, PFNA, and related chemicals) in Stafford 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 Stafford County

18 Active public water systems

127,351 Residents on public water

24% Households on private wells

Public water systems in Stafford 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 Stafford 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	Stafford County Prevalence	VA Average	Source Year
PFOS	Cancer prevalence	5.8%	6.7%	2020
Arsenic	Kidney disease rate	2.3%	3.1%	2020

Data Sources

This report aggregates data from the following public databases:

Water Quality Portal (WQP) — groundwater sample results for Stafford County from EPA, USGS, and state agencies. Browse WQP data →
EPA Safe Drinking Water Information System (SDWIS) — public water system inventory used to estimate the share of residents on private wells. Browse SDWIS →
Census ACS 5-Year Estimates — well and cistern household counts (variable DP04_0074E) used to calculate the private-well percentage for Stafford County. Census data explorer →
USGS Aquifer Atlas — principal aquifer type underlying Stafford County, which informs which contaminants are geologically likely. USGS Aquifer Atlas →
EPA UCMR 5 (2023–2025) — PFAS occurrence data from public water systems, used as a proxy indicator for aquifer PFAS exposure. Rows marked "municipal" in the table above come from this source. About UCMR 5 →
EPA Toxics Release Inventory (TRI) — industrial facility chemical releases near Stafford County, used in contamination risk scoring. TRI Explorer →
EPA Superfund NPL — National Priorities List sites in or near Stafford County, used in contamination risk scoring. Superfund site search →
CDC PLACES — county-level health outcome prevalence (kidney disease, cancer, heart disease) correlated with detected contaminants. About CDC PLACES →

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: 2026-08-04

Full methodology →