Data & Methodology — Isanti County

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

Contaminant Data — All Analytes

329 well testing events on record, covering 19 analytes. Data spans 1956 to 2024.

Contaminant Samples Years Detection Rate Distribution LowModHigh vs. Limit vs. MN Avg
PFOA municipal 24 2024–2025 83%
1420% of limit ↑ 230% above
Manganese 246 1968–2018 89%
382% of limit ↓ 22% below
PFOS municipal 21 2024–2025 81%
650% of limit ↑ 223% above
PFHxS municipal 8 2024–2025 50%
390% of limit ↑ 388% above
PFNA municipal 14 2024–2025 71%
185% of limit ↑ 1014% above
Nitrate 96 1968–2010 83%
126% of limit ↑ 421% above
Iron 248 1968–2019 58%
91% of limit ↓ 87% below
Arsenic 133 1996–2018 72%
27% of limit ↓ 69% below
Chloride 289 1968–2025 98%
4% of limit ↓ 43% below
Lead 224 1972–2018 9%
5% of limit ↓ 89% below
Fluoride 147 1968–2019 88%
4% of limit ↓ 35% below
HFPO-DA (GenX) municipal 4 2024–2025 0%
— —
Nitrite 27 1984–2010 30%
1% of limit ↑ 24% above
Sulfate 266 1968–2019 91%
4% of limit ↓ 77% below
Uranium 3 2010 0%
— —
Sodium 248 1968–2019 100%
— ↓ 79% below
pH 77 1968–2013 100%
— ~ typical
PFBS municipal 6 2024–2025 33%
— ~ typical
Hardness 28 1968–1990 100%
— ↓ 21% 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 Isanti County

Of the 133 arsenic tests on record for Isanti County (1996–2018), 28% found none, and half were below 1.44 µg/L.

Of the 289 chloride tests on record for Isanti County (1968–2025), 2% found none, and half were below 10.5 mg/L.

Of the 147 fluoride tests on record for Isanti County (1968–2019), 12% found none, and half were below 170 µg/L.

Of the 248 iron tests on record for Isanti County (1968–2019), 42% found none, and half were below 8 µg/L.

Of the 224 lead tests on record for Isanti County (1972–2018), 91% found none.

Of the 246 manganese tests on record for Isanti County (1968–2018), 11% found none, and half were below 147 µg/L.

Of the 96 nitrate tests on record for Isanti County (1968–2010), 17% found none, and half were below 6.88 mg/L.

Of the 20 pfoa tests on record for Isanti County, 0% found none, and half were below 56.8 ng/L.

Of the 266 sulfate tests on record for Isanti County (1968–2019), 9% found none, and half were below 8.9 mg/L.

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Data Coverage & Gaps

Well-sampled analytes (15+ samples)

  • PFOA 24 samples
  • Manganese 246 samples
  • PFOS 21 samples
  • Nitrate 96 samples
  • Iron 248 samples
  • Arsenic 133 samples
  • Chloride 289 samples
  • Lead 224 samples
  • Fluoride 147 samples
  • Nitrite 27 samples
  • Sulfate 266 samples
  • Sodium 248 samples
  • pH 77 samples
  • Hardness 28 samples

Limited data (<15 samples) — interpret with caution

  • PFHxS 8 samples
  • PFNA 14 samples
  • Uranium 3 samples
  • PFBS 6 samples

Public vs. Private Water in Isanti County

70 Active public water systems
27,746 Residents on public water
60% Households on private wells

Public water systems in Isanti 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 Isanti 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 Isanti County Prevalence MN Average Source Year
Arsenic Cancer prevalence 7.3% 7.0% 2020
Arsenic Kidney disease rate 2.9% 2.9% 2020
Lead Heart disease rate 6.7% 6.6% 2020

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