Data & Methodology — Montgomery County

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

Contaminant Data — All Analytes

539 well testing events on record, covering 22 analytes. Data spans 1961 to 2022.

Contaminant Samples Years Detection Rate Distribution LowModHigh vs. Limit vs. OH Avg
Manganese 472 1972–2020 92%
319% of limit ↑ 81% above
Iron 483 1972–2020 88%
327% of limit ↓ 25% below
PFOS municipal 54 2023–2025 30%
180% of limit ~ typical
Arsenic 307 1972–2020 84%
10% of limit ↓ 37% below
PFHxS municipal 54 2023–2025 35%
90% of limit ↑ 69% above
PFOA municipal 55 2008–2025 2%
120% of limit ~ typical
Chloride 482 1972–2020 100%
22% of limit ↑ 48% above
Nitrate 246 1972–2020 85%
7% of limit ↑ 51% above
Sulfate 297 1972–2020 100%
25% of limit ↓ 44% below
Lead 303 1972–2020 66%
0% of limit ↓ 100% below
Fluoride 319 1972–2020 97%
8% of limit ↓ 27% below
HFPO-DA (GenX) municipal 54 2023–2025 0%
— —
Nitrite 223 1973–2020 39%
2% of limit ↑ 214% above
PFNA municipal 55 2008–2025 0%
— —
Radon 11 1999–2001 100%
9% of limit ↓ 61% below
Uranium 47 1999–2020 98%
4% of limit ↑ 70% above
E. coli 3 2002–2019 0%
— —
Hardness 470 1972–2020 100%
— ~ typical
PFBS municipal 54 2023–2025 28%
— ~ typical
pH 455 1972–2020 100%
— ~ typical
Sodium 439 1976–2020 100%
— ~ typical
Total Coliform 3 2002–2019 36%
— ~ 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 OH.

Compare your result with Montgomery County

Of the 307 arsenic tests on record for Montgomery County (1972–2020), 16% found none, and half were below 0.3 µg/L.

Of the 482 chloride tests on record for Montgomery County (1972–2020), 0% found none, and half were below 56 mg/L.

Of the 319 fluoride tests on record for Montgomery County (1972–2020), 3% found none, and half were below 300 µg/L.

Of the 483 iron tests on record for Montgomery County (1972–2020), 12% found none, and half were below 489 µg/L.

Of the 303 lead tests on record for Montgomery County (1972–2020), 34% found none.

Of the 472 manganese tests on record for Montgomery County (1972–2020), 8% found none, and half were below 150 µg/L.

Of the 246 nitrate tests on record for Montgomery County (1972–2020), 15% found none, and half were below 376 µg/L.

Of the 297 sulfate tests on record for Montgomery County (1972–2020), 0% found none, and half were below 62 mg/L.

Of the 47 uranium tests on record for Montgomery County (1999–2020), 2% found none, and half were below 1.16 µg/L.

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Data Coverage & Gaps

Well-sampled analytes (15+ samples)

  • Manganese 472 samples
  • Iron 483 samples
  • Arsenic 307 samples
  • PFOA 55 samples
  • Chloride 482 samples
  • Nitrate 246 samples
  • Sulfate 297 samples
  • Lead 303 samples
  • Fluoride 319 samples
  • Nitrite 223 samples
  • PFNA 55 samples
  • Uranium 47 samples
  • Hardness 470 samples
  • pH 455 samples
  • Sodium 439 samples

Limited data (<15 samples) — interpret with caution

  • Radon 11 samples
  • E. coli 3 samples
  • Total Coliform 3 samples

Public vs. Private Water in Montgomery County

73 Active public water systems
524,863 Residents on public water
2% Households on private wells

Public water systems in Montgomery 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 Montgomery 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 Montgomery County Prevalence OH Average Source Year
Arsenic Cancer prevalence 6.1% 6.8% 2020
Arsenic Kidney disease rate 3.0% 3.1% 2020
Lead Heart disease rate 7.8% 7.6% 2020

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