Data & Methodology — Chatham County

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

Contaminant Data — All Analytes

2095 well testing events on record, covering 18 analytes. Data spans 1938 to 2026.

Contaminant Samples Years Detection Rate Distribution LowModHigh vs. Limit vs. GA Avg
Chloride 2030 1938–2015 99%
240% of limit ↑ 12753% above
Sulfate 279 1938–2015 96%
27% of limit ↑ 1233% above
Manganese 38 1967–2015 34%
230% of limit ↑ 283% above
Iron 57 1964–2015 68%
47% of limit ~ typical
PFOA municipal 92 2023–2025 14%
118% of limit ~ typical
PFOS municipal 92 2023–2025 10%
130% of limit ~ typical
Nitrate 234 1938–2015 70%
0% of limit ↓ 95% below
Fluoride 160 1938–2015 96%
18% of limit ↑ 250% above
HFPO-DA (GenX) municipal 92 2023–2025 0%
— —
Nitrite 34 1970–2015 3%
0% of limit ↓ 100% below
Lead 9 1967–2015 44%
0% of limit ↓ 90% below
PFHxS municipal 92 2023–2025 0%
— —
PFNA municipal 92 2023–2025 0%
— —
Arsenic 9 1970–2015 56%
5% of limit ~ typical
Hardness 161 1938–2015 100%
— ↑ 56% above
PFBS municipal 92 2023–2025 12%
— ~ typical
Sodium 147 1938–2015 100%
— ↑ 652% above
pH 224 1938–2015 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 GA.

Data Coverage & Gaps

Well-sampled analytes (15+ samples)

  • Chloride 2030 samples
  • Sulfate 279 samples
  • Manganese 38 samples
  • Iron 57 samples
  • Nitrate 234 samples
  • Fluoride 160 samples
  • Nitrite 34 samples
  • Hardness 161 samples
  • Sodium 147 samples
  • pH 224 samples

Limited data (<15 samples) — interpret with caution

  • Lead 9 samples
  • Arsenic 9 samples

No private-well PFAS data for Chatham County

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

117 Active public water systems
347,409 Residents on public water

Public water systems in Chatham 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 Chatham 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 Chatham County Prevalence GA Average Source Year
Nitrate Cancer prevalence 5.7% 6.3% 2020

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

Last updated: 2026-08-03

Full methodology →