Data & Methodology — Todd County

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

Contaminant Data — All Analytes

202 well testing events on record, covering 18 analytes. Data spans 1948 to 2023.

Contaminant Samples Years Detection Rate Distribution LowModHigh vs. Limit vs. MN Avg
Iron 150 1964–2010 96%
409% of limit ↓ 43% below
Manganese 159 1964–2010 94%
329% of limit ↓ 33% below
PFOA municipal 11 2005–2023 73%
198% of limit ↓ 54% below
PFHxS municipal 5 2023 60%
130% of limit ↑ 62% above
PFOS municipal 7 2023 71%
92% of limit ↓ 54% below
Arsenic 111 1994–2010 41%
106% of limit ↑ 24% above
Nitrate 154 1964–2008 79%
1% of limit ↓ 97% below
Lead 120 1994–2010 70%
52% of limit ~ typical
Chloride 180 1964–2025 99%
2% of limit ↓ 77% below
Fluoride 114 1964–2008 88%
5% of limit ↓ 28% below
HFPO-DA (GenX) municipal 2 2023 0%
— —
Nitrite 107 1991–2008 55%
1% of limit ~ typical
PFNA municipal 5 2006–2023 40%
15% of limit ~ typical
Sulfate 149 1964–2010 99%
6% of limit ↓ 69% below
Hardness 28 1964–1979 100%
— ~ typical
PFBS municipal 3 2023 33%
— ↓ 25% below
pH 50 1964–2010 100%
— ~ typical
Sodium 146 1964–2010 100%
— ↓ 69% 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 MN.

Compare your result with Todd County

Of the 111 arsenic tests on record for Todd County (1994–2010), 59% found none.

Of the 180 chloride tests on record for Todd County (1964–2025), 1% found none, and half were below 4.43 mg/L.

Of the 114 fluoride tests on record for Todd County (1964–2008), 12% found none, and half were below 190 µg/L.

Of the 150 iron tests on record for Todd County (1964–2010), 4% found none, and half were below 1.08 mg/L.

Of the 120 lead tests on record for Todd County (1994–2010), 30% found none, and half were below 7.05 µg/L.

Of the 159 manganese tests on record for Todd County (1964–2010), 6% found none, and half were below 160 µg/L.

Of the 154 nitrate tests on record for Todd County (1964–2008), 21% found none, and half were below 20.5 µg/L.

Of the 149 sulfate tests on record for Todd County (1964–2010), 1% found none, and half were below 14.2 mg/L.

Have a number from your lab? Enter it to see where it falls. Nothing is sent anywhere.

Want the full picture for your well? Check all your results.

Data Coverage & Gaps

Well-sampled analytes (15+ samples)

  • Iron 150 samples
  • Manganese 159 samples
  • Arsenic 111 samples
  • Nitrate 154 samples
  • Lead 120 samples
  • Chloride 180 samples
  • Fluoride 114 samples
  • Nitrite 107 samples
  • Sulfate 149 samples
  • Hardness 28 samples
  • pH 50 samples
  • Sodium 146 samples

Limited data (<15 samples) — interpret with caution

  • PFOA 11 samples
  • PFHxS 5 samples
  • PFOS 7 samples
  • PFNA 5 samples
  • PFBS 3 samples

Public vs. Private Water in Todd County

73 Active public water systems
15,609 Residents on public water
66% Households on private wells

Public water systems in Todd 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 Todd 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 Todd County Prevalence MN Average Source Year
Arsenic Cancer prevalence 6.0% 7.0% 2020
Arsenic Kidney disease rate 2.8% 2.9% 2020
Lead Heart disease rate 9.2% 6.6% 2020

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

Last updated: 2026-08-04

Full methodology →