Data & Methodology — Otsego County

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

Contaminant Data — All Analytes

10 well testing events on record, covering 20 analytes. Data spans 1966 to 2012.

Contaminant Samples Years Detection Rate Distribution LowModHigh vs. Limit vs. MI Avg
Iron 3 1977–1984 100%
20% of limit ↓ 90% below
Arsenic 3 1977–1984 67%
10% of limit ↓ 69% below
Chloride 3 1977–1984 100%
5% of limit ↓ 58% below
Fluoride 3 1977–1984 33%
2% of limit ↓ 69% below
HFPO-DA (GenX) municipal 10 2024–2025 0%
— —
Lead 3 1977–1984 0%
— —
Manganese 3 1977–1984 67%
20% of limit ↓ 85% below
Nitrate 3 1977–1984 100%
3% of limit ~ typical
Nitrite 3 1977–1984 33%
1% of limit ↑ 129% above
PFHxS municipal 10 2024–2025 0%
— —
PFNA municipal 10 2024–2025 0%
— —
PFOA municipal 10 2024–2025 0%
— —
PFOS municipal 10 2024–2025 0%
— —
Radon 1 1991 100%
5% of limit ↓ 86% below
Sulfate 3 1977–1984 100%
5% of limit ↓ 70% below
Uranium 2 1979–1984 50%
1% of limit ↓ 41% below
Hardness 3 1977–1984 100%
— ↑ 102% above
PFBS municipal 10 2024–2025 20%
— —
pH 6 1977–1991 100%
— ~ typical
Sodium 3 1977–1984 100%
— ↓ 70% 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 MI.

Data Coverage & Gaps

Limited data (<15 samples) — interpret with caution

  • Iron 3 samples
  • Arsenic 3 samples
  • Chloride 3 samples
  • Fluoride 3 samples
  • Lead 3 samples
  • Manganese 3 samples
  • Nitrate 3 samples
  • Nitrite 3 samples
  • Radon 1 sample
  • Sulfate 3 samples
  • Uranium 2 samples
  • Hardness 3 samples
  • pH 6 samples
  • Sodium 3 samples

No private-well PFAS data for Otsego County

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

126 Active public water systems
21,534 Residents on public water
15% Households on private wells

Public water systems in Otsego 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.

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 MI with at least one sample for that analyte.

Last updated: 2026-07-15

Full methodology →