Data & Methodology — Rockingham County

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

Contaminant Data — All Analytes

1022 well testing events on record, covering 9 analytes. Data spans 1930 to 2025.

Contaminant Samples Years Detection Rate Distribution LowModHigh vs. Limit vs. VA Avg
Manganese 181 1993–2022 49%
83% of limit ↓ 33% below
Iron 184 1970–2022 65%
20% of limit ↓ 83% below
Nitrate 199 1970–2025 93%
42% of limit ↑ 1058% above
E. coli 1 2004–2022 99%
— ~ typical
Hardness 188 1970–2025 100%
— ↑ 125% above
PFBS municipal 24 2023–2025 0%
— —
pH 199 1970–2022 100%
— ~ typical
Sodium 188 1970–2025 100%
— ↓ 80% below
Total Coliform 1 2013–2022 33%
— ~ 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.

Compare your result with Rockingham County

Of the 45 arsenic tests on record for Rockingham County (1998–2022), 29% found none, and half were below 0.1 µg/L.

Of the 186 chloride tests on record for Rockingham County (1970–2025), 0% found none, and half were below 5.83 mg/L.

Of the 180 fluoride tests on record for Rockingham County (1970–2025), 49% found none, and half were below 15 µg/L.

Of the 184 iron tests on record for Rockingham County (1970–2022), 35% found none, and half were below 35 µg/L.

Of the 45 lead tests on record for Rockingham County (1998–2022), 69% found none.

Of the 181 manganese tests on record for Rockingham County (1993–2022), 51% found none.

Of the 199 nitrate tests on record for Rockingham County (1970–2025), 7% found none, and half were below 3.92 mg/L.

Of the 186 sulfate tests on record for Rockingham County (1970–2025), 0% found none, and half were below 10.4 mg/L.

Of the 20 uranium tests on record for Rockingham County (1993–2022), 25% found none, and half were below 0.247 µg/L.

Have a number from your lab? Enter it to see where it falls. Nothing is sent anywhere.

Want the full picture for your well? Check all your results.

Data Coverage & Gaps

Well-sampled analytes (15+ samples)

  • Manganese 181 samples
  • Iron 184 samples
  • Nitrate 199 samples
  • Hardness 188 samples
  • pH 199 samples
  • Sodium 188 samples

Limited data (<15 samples) — interpret with caution

  • E. coli 1 sample
  • Total Coliform 1 sample

No private-well PFAS data for Rockingham County

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

63 Active public water systems
51,761 Residents on public water
53% Households on private wells

Public water systems in Rockingham 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 Rockingham 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 Rockingham County Prevalence VA Average Source Year
Nitrate Cancer prevalence 7.6% 6.7% 2020

Source: CDC PLACES county-level estimates. Raw data: Download Rockingham 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: 2026-08-04

Full methodology →