Data & Methodology — Wake County

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

Contaminant Data — All Analytes

150 well testing events on record, covering 20 analytes. Data spans 1958 to 2023.

Contaminant Samples Years Detection Rate Distribution LowModHigh vs. Limit vs. NC Avg
Manganese 102 1961–2019 100%
82% of limit ~ typical
Nitrate 90 1961–2007 94%
61% of limit ↑ 719% above
Iron 102 1961–2019 65%
10% of limit ↓ 96% below
PFOA municipal 242 2023–2025 11%
136% of limit ~ typical
PFOS municipal 242 2023–2025 11%
172% of limit ~ typical
Uranium 22 2002–2007 95%
0% of limit ↓ 62% below
Nitrite 74 2001–2007 43%
1% of limit ~ typical
PFHxS municipal 242 2023–2025 14%
44% of limit ~ typical
Chloride 103 1961–2019 100%
4% of limit ↓ 32% below
Arsenic 53 2001–2007 28%
4% of limit ~ typical
Fluoride 86 1961–2007 51%
3% of limit ↓ 50% below
HFPO-DA (GenX) municipal 242 2023–2025 0%
— —
Lead 22 2002–2007 55%
1% of limit ↓ 70% below
PFNA municipal 242 2023–2025 0%
— —
Radon 31 2001–2007 100%
17% of limit ↓ 32% below
Sulfate 103 1961–2019 100%
1% of limit ↓ 78% below
Hardness 103 1961–2019 100%
— ~ typical
PFBS municipal 242 2023–2025 24%
— ~ typical
pH 108 1961–2019 100%
— ~ typical
Sodium 103 1961–2019 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 NC.

Compare your result with Wake County

Of the 53 arsenic tests on record for Wake County (2001–2007), 72% found none.

Of the 103 chloride tests on record for Wake County (1961–2019), 0% found none, and half were below 10.7 mg/L.

Of the 86 fluoride tests on record for Wake County (1961–2007), 49% found none.

Of the 102 iron tests on record for Wake County (1961–2019), 35% found none, and half were below 10 µg/L.

Of the 22 lead tests on record for Wake County (2002–2007), 45% found none, and half were below 48.5 ng/L.

Of the 102 manganese tests on record for Wake County (1961–2019), 0% found none, and half were below 41 µg/L.

Of the 90 nitrate tests on record for Wake County (1961–2007), 6% found none, and half were below 5.77 mg/L.

Of the 103 sulfate tests on record for Wake County (1961–2019), 0% found none, and half were below 2 mg/L.

Of the 22 uranium tests on record for Wake County (2002–2007), 5% found none, and half were below 55 ng/L.

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Data Coverage & Gaps

Well-sampled analytes (15+ samples)

  • Manganese 102 samples
  • Nitrate 90 samples
  • Iron 102 samples
  • Uranium 22 samples
  • Nitrite 74 samples
  • Chloride 103 samples
  • Arsenic 53 samples
  • Fluoride 86 samples
  • Lead 22 samples
  • Radon 31 samples
  • Sulfate 103 samples
  • Hardness 103 samples
  • pH 108 samples
  • Sodium 103 samples

No private-well PFAS data for Wake County

We have no private well sampling data for PFAS compounds (PFOA, PFOS, PFNA, and related chemicals) in Wake 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 Wake 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 Wake County Prevalence NC Average Source Year
Lead Heart disease rate 4.8% 7.4% 2020
Nitrate Cancer prevalence 5.6% 6.7% 2020
Uranium Kidney disease rate 2.4% 3.4% 2020

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