Data & Methodology — Accomack County

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

Contaminant Data — All Analytes

957 well testing events on record, covering 19 analytes. Data spans 1906 to 2026.

Contaminant Samples Years Detection Rate Distribution LowModHigh vs. Limit vs. VA Avg
Iron 135 1906–2023 70%
13% of limit ↓ 83% below
Manganese 81 1987–2023 57%
89% of limit ↓ 29% below
Chloride 178 1906–2026 100%
10% of limit ~ typical
Nitrate 104 1906–2026 88%
2% of limit ↓ 70% below
Arsenic 52 1988–2023 48%
10% of limit ↑ 32% above
Sulfate 147 1906–2026 94%
3% of limit ↓ 70% below
PFNA municipal 12 2024–2025 0%
— —
HFPO-DA (GenX) municipal 12 2024–2025 0%
— —
Uranium 40 1998–2023 35%
0% of limit ↓ 79% below
Nitrite 54 1975–2026 41%
1% of limit ~ typical
PFHxS municipal 12 2024–2025 0%
— —
Fluoride 146 1948–2026 71%
5% of limit ↑ 33% above
Radon 24 1988–2012 79%
8% of limit ↓ 90% below
Lead 52 1988–2023 23%
1% of limit ↓ 69% below
PFOS municipal 12 2024–2025 0%
— —
Sodium 147 1906–2026 100%
— ↑ 54% above
pH 184 1948–2023 100%
— ~ typical
PFBS municipal 12 2024–2025 0%
— —
Hardness 147 1906–2026 100%
— ↑ 34% above

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 135 samples
  • Manganese 81 samples
  • Chloride 178 samples
  • Nitrate 104 samples
  • Arsenic 52 samples
  • Sulfate 147 samples
  • Uranium 40 samples
  • Nitrite 54 samples
  • Fluoride 146 samples
  • Radon 24 samples
  • Lead 52 samples
  • Sodium 147 samples
  • pH 184 samples
  • Hardness 147 samples

No private-well PFAS data for Accomack County

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

89 Active public water systems
36,803 Residents on public water

Public water systems in Accomack 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 Accomack 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 Accomack County Prevalence VA Average Source Year
Arsenic Cancer prevalence 5.8% 6.7% 2020
Arsenic Kidney disease rate 3.2% 3.1% 2020

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