Data & Methodology — Iredell County

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

Contaminant Data — All Analytes

94 well testing events on record, covering 20 analytes. Data spans 1955 to 2014.

Contaminant Samples Years Detection Rate Distribution LowModHigh vs. Limit vs. NC Avg
Manganese 47 2002–2014 96%
13% of limit ↓ 85% below
PFOA municipal 135 2023–2025 7%
150% of limit ~ typical
PFOS municipal 135 2023–2025 4%
112% of limit ↓ 25% below
Radon 37 2002–2014 100%
7% of limit ↓ 70% below
Arsenic 47 2002–2014 11%
10% of limit ↑ 120% above
Chloride 47 2002–2014 100%
1% of limit ↓ 89% below
Fluoride 47 2002–2014 28%
2% of limit ↓ 68% below
HFPO-DA (GenX) municipal 135 2023–2025 0%
— —
Iron 47 2002–2014 21%
4% of limit ↓ 99% below
Lead 34 2003–2014 38%
1% of limit ↓ 54% below
Nitrate 53 2002–2014 64%
7% of limit ~ typical
Nitrite 53 2002–2014 15%
0% of limit ↓ 59% below
PFHxS municipal 135 2023–2025 4%
36% of limit ~ typical
PFNA municipal 135 2023–2025 0%
— —
Sulfate 47 2002–2014 98%
1% of limit ↓ 83% below
Uranium 40 2003–2014 60%
0% of limit ~ typical
Hardness 47 2002–2014 100%
— ↓ 62% below
PFBS municipal 135 2023–2025 10%
— ~ typical
pH 48 2002–2014 100%
— ~ typical
Sodium 47 2002–2014 100%
— ↓ 71% 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 NC.

Compare your result with Iredell County

Of the 47 arsenic tests on record for Iredell County (2002–2014), 89% found none.

Of the 47 chloride tests on record for Iredell County (2002–2014), 0% found none, and half were below 1.75 mg/L.

Of the 47 fluoride tests on record for Iredell County (2002–2014), 72% found none.

Of the 47 iron tests on record for Iredell County (2002–2014), 79% found none.

Of the 34 lead tests on record for Iredell County (2003–2014), 62% found none.

Of the 47 manganese tests on record for Iredell County (2002–2014), 4% found none, and half were below 5.98 µg/L.

Of the 53 nitrate tests on record for Iredell County (2002–2014), 36% found none, and half were below 214 µg/L.

Of the 47 sulfate tests on record for Iredell County (2002–2014), 2% found none, and half were below 1.51 mg/L.

Of the 40 uranium tests on record for Iredell County (2003–2014), 40% found none, and half were below 20 ng/L.

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Data Coverage & Gaps

Well-sampled analytes (15+ samples)

  • Manganese 47 samples
  • Radon 37 samples
  • Arsenic 47 samples
  • Chloride 47 samples
  • Fluoride 47 samples
  • Iron 47 samples
  • Lead 34 samples
  • Nitrate 53 samples
  • Nitrite 53 samples
  • Sulfate 47 samples
  • Uranium 40 samples
  • Hardness 47 samples
  • pH 48 samples
  • Sodium 47 samples

No private-well PFAS data for Iredell County

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

CDC Health Outcome Correlations

Where contaminants detected in Iredell 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 Iredell County Prevalence NC Average Source Year
PFOA Cancer prevalence 7.0% 6.7% 2020

Source: CDC PLACES county-level estimates. Raw data: Download Iredell 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 NC with at least one sample for that analyte.

Last updated: 2026-08-04

Full methodology →