Data & Methodology — Richland County

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

Contaminant Data — All Analytes

2014 well testing events on record, covering 18 analytes. Data spans 1965 to 2017.

Contaminant Samples Years Detection Rate Distribution LowModHigh vs. Limit vs. OH Avg
Manganese 99 1977–2014 91%
438% of limit ↑ 148% above
Iron 118 1974–2014 92%
304% of limit ↓ 31% below
Arsenic 86 1987–2014 78%
70% of limit ↑ 344% above
Lead 96 1974–2014 60%
0% of limit ↓ 100% below
Chloride 1971 1974–2014 100%
15% of limit ~ typical
Fluoride 101 1974–2014 55%
8% of limit ~ typical
HFPO-DA (GenX) municipal 13 2023–2025 0%
— —
Nitrate 50 1974–1999 100%
0% of limit ↓ 98% below
Nitrite 22 1991–1999 36%
2% of limit ↑ 143% above
PFHxS municipal 13 2023–2025 0%
— —
PFNA municipal 13 2023–2025 0%
— —
PFOA municipal 13 2023–2025 0%
— —
PFOS municipal 13 2023–2025 0%
— —
Sulfate 62 1991–2014 98%
10% of limit ↓ 76% below
Hardness 81 1974–2014 100%
— ↓ 30% below
PFBS municipal 13 2023–2025 0%
— —
pH 729 1974–2005 100%
— ~ typical
Sodium 1712 1974–2014 99%
— ↓ 75% 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 OH.

Compare your result with Richland County

Of the 86 arsenic tests on record for Richland County (1987–2014), 22% found none, and half were below 6.4 µg/L.

Of the 1971 chloride tests on record for Richland County (1974–2014), 0% found none, and half were below 37 mg/L.

Of the 101 fluoride tests on record for Richland County (1974–2014), 45% found none, and half were below 150 µg/L.

Of the 118 iron tests on record for Richland County (1974–2014), 8% found none, and half were below 893 µg/L.

Of the 96 lead tests on record for Richland County (1974–2014), 40% found none.

Of the 99 manganese tests on record for Richland County (1977–2014), 9% found none, and half were below 207 µg/L.

Of the 50 nitrate tests on record for Richland County (1974–1999), 0% found none, and half were below 10 µg/L.

Of the 62 sulfate tests on record for Richland County (1991–2014), 2% found none, and half were below 26 mg/L.

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Data Coverage & Gaps

Well-sampled analytes (15+ samples)

  • Manganese 99 samples
  • Iron 118 samples
  • Arsenic 86 samples
  • Lead 96 samples
  • Chloride 1971 samples
  • Fluoride 101 samples
  • Nitrate 50 samples
  • Nitrite 22 samples
  • Sulfate 62 samples
  • Hardness 81 samples
  • pH 729 samples
  • Sodium 1712 samples

No private-well PFAS data for Richland County

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

120 Active public water systems
104,649 Residents on public water
24% Households on private wells

Public water systems in Richland 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 Richland 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 Richland County Prevalence OH Average Source Year
Lead Heart disease rate 8.6% 7.6% 2020
Arsenic Cancer prevalence 5.9% 6.8% 2020
Arsenic Kidney disease rate 2.9% 3.1% 2020

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

Last updated: 2026-08-04

Full methodology →