Full contaminant data, sample history, and sourcing for McLeod County. For readers who want to go beyond the summary.
Contaminant Data — All Analytes
94 well testing events on record, covering
19 analytes.
Data spans 1947 to 2022.
Contaminant
Samples
Years
Detection Rate
Distribution LowModHigh
vs. Limit
vs. MN Avg
Iron
89
1971–2011
100%
543% of limit
↓ 24% below
Manganese
86
1971–2011
99%
148% of limit
↓ 70% below
Arsenic
82
1994–2011
93%
132% of limit
↑ 54% above
Uranium
79
1980–2011
92%
0% of limit
↓ 88% below
Sulfate
88
1971–2011
100%
16% of limit
~ typical
Chloride
89
1971–2011
100%
1% of limit
↓ 93% below
Fluoride
88
1971–2011
99%
6% of limit
~ typical
HFPO-DA (GenX)
municipal
6
2023–2024
0%
—
—
Lead
82
1994–2011
79%
0% of limit
↓ 99% below
Nitrate
84
1974–2011
82%
0% of limit
↓ 100% below
Nitrite
79
1974–2011
9%
0% of limit
↓ 90% below
PFHxS
municipal
6
2023–2024
0%
—
—
PFNA
municipal
6
2023–2024
0%
—
—
PFOA
municipal
6
2023–2024
0%
—
—
PFOS
municipal
6
2023–2024
0%
—
—
Sodium
88
1971–2011
100%
—
↑ 25% above
pH
7
1971–1980
100%
—
~ typical
PFBS
municipal
6
2023–2024
0%
—
—
Hardness
6
1971–1978
100%
—
↑ 34% above
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 McLeod County
Of the 82 arsenic tests on record for McLeod County (1994–2011),
7% found none, and half were below 11.9 µg/L.
Of the 89 chloride tests on record for McLeod County (1971–2011),
0% found none, and half were below 1.27 mg/L.
Of the 88 fluoride tests on record for McLeod County (1971–2011),
1% found none, and half were below 254 µg/L.
Of the 89 iron tests on record for McLeod County (1971–2011),
0% found none, and half were below 1.63 mg/L.
Of the 82 lead tests on record for McLeod County (1994–2011),
21% found none, and half were below 53 ng/L.
Of the 86 manganese tests on record for McLeod County (1971–2011),
1% found none, and half were below 73.2 µg/L.
Of the 84 nitrate tests on record for McLeod County (1974–2011),
18% found none, and half were below 5 µg/L.
Of the 88 sulfate tests on record for McLeod County (1971–2011),
0% found none, and half were below 39.5 mg/L.
Of the 79 uranium tests on record for McLeod County (1980–2011),
8% found none, and half were below 0.13 µg/L.
Data Coverage & Gaps
Well-sampled analytes (15+ samples)
Iron 89 samples
Manganese 86 samples
Arsenic 82 samples
Uranium 79 samples
Sulfate 88 samples
Chloride 89 samples
Fluoride 88 samples
Lead 82 samples
Nitrate 84 samples
Nitrite 79 samples
Sodium 88 samples
Limited data (<15 samples) — interpret with caution
pH 7 samples
Hardness 6 samples
No private-well PFAS data for McLeod County
We have no private well sampling data for PFAS compounds (PFOA, PFOS, PFNA, and related chemicals) in McLeod County.
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 McLeod County
39Active public water systems
31,088Residents on public water
27%Households on private wells
Public water systems in McLeod 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 McLeod 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.
This report aggregates data from the following public databases:
Water Quality Portal (WQP) — groundwater sample results for McLeod County from EPA, USGS, and state agencies. Browse WQP data →
EPA Safe Drinking Water Information System (SDWIS) — public water system inventory used to estimate the share of residents on private wells. Browse SDWIS →
Census ACS 5-Year Estimates — well and cistern household counts (variable DP04_0074E) used to calculate the private-well percentage for McLeod County. Census data explorer →
USGS Aquifer Atlas — principal aquifer type underlying McLeod County, which informs which contaminants are geologically likely. USGS Aquifer Atlas →
EPA UCMR 5 (2023–2025) — PFAS occurrence data from public water systems, used as a proxy indicator for aquifer PFAS exposure. Rows marked "municipal" in the table above come from this source. About UCMR 5 →
EPA Toxics Release Inventory (TRI) — industrial facility chemical releases near McLeod County, used in contamination risk scoring. TRI Explorer →
EPA Superfund NPL — National Priorities List sites in or near McLeod County, used in contamination risk scoring. Superfund site search →
CDC PLACES — county-level health outcome prevalence (kidney disease, cancer, heart disease) correlated with detected contaminants. About CDC PLACES →
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.