Data & Methodology — Anoka County

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

Contaminant Data — All Analytes

1223 well testing events on record, covering 20 analytes. Data spans 1954 to 2025.

Contaminant Samples Years Detection Rate Distribution LowModHigh vs. Limit vs. MN Avg
Manganese 683 1960–2025 64%
380% of limit ~ typical
PFOA municipal 649 2006–2025 80%
110% of limit ↑ 2833% above
PFOS municipal 491 2023–2025 75%
105% of limit —
PFHxS municipal 322 2023–2025 73%
70% of limit —
Iron 851 1960–2025 68%
53% of limit ↓ 90% below
Arsenic 604 1996–2025 32%
27% of limit ↓ 66% below
Chloride 964 1960–2025 96%
8% of limit ↓ 36% below
Nitrate 314 1960–2016 63%
10% of limit ↓ 50% below
Sulfate 843 1960–2025 97%
4% of limit ↓ 81% below
PFNA municipal 242 2006–2025 34%
6% of limit —
Nitrite 175 1984–2016 17%
3% of limit ~ typical
Lead 604 1996–2025 8%
0% of limit ↓ 99% below
Fluoride 433 1960–2025 59%
3% of limit ↓ 61% below
HFPO-DA (GenX) municipal 161 2022–2025 1%
27% of limit —
Radon 2 1996–2014 100%
52% of limit ↓ 35% below
Uranium 125 1996–2016 74%
2% of limit ↓ 57% below
Hardness 173 1960–2016 100%
— ~ typical
Sodium 788 1960–2025 100%
— ↓ 69% below
pH 331 1960–2020 100%
— ~ typical
PFBS municipal 334 2023–2025 73%
— —

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.

Data Coverage & Gaps

Well-sampled analytes (15+ samples)

  • Manganese 683 samples
  • PFOA 649 samples
  • PFOS 491 samples
  • PFHxS 322 samples
  • Iron 851 samples
  • Arsenic 604 samples
  • Chloride 964 samples
  • Nitrate 314 samples
  • Sulfate 843 samples
  • PFNA 242 samples
  • Nitrite 175 samples
  • Lead 604 samples
  • Fluoride 433 samples
  • HFPO-DA (GenX) 161 samples
  • Uranium 125 samples
  • Hardness 173 samples
  • Sodium 788 samples
  • pH 331 samples
  • PFBS 334 samples

Limited data (<15 samples) — interpret with caution

  • Radon 2 samples

Public vs. Private Water in Anoka County

245 Active public water systems
328,078 Residents on public water

Public water systems in Anoka 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 Anoka 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 Anoka County Prevalence MN Average Source Year
Lead Heart disease rate 5.2% 6.6% 2020
Arsenic Cancer prevalence 5.9% 7.0% 2020
Arsenic Kidney disease rate 2.4% 2.9% 2020

Source: CDC PLACES county-level estimates. Raw data: Download Anoka 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: 2026-07-15

Full methodology →