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Minnesota water profile

Nitrate in Minnesota community water systems

Minnesota's nitrate risk sits in vulnerable farm country — the central sand plains, the southeastern karst, and the intensively farmed southwest — while most of the state's fine glacial soils keep groundwater low. See where higher public-system results concentrate and what each reporting system measured in the three years from August 9, 2023 to August 9, 2026.

Browse all 135 Minnesota systems →

Search by the utility or system name shown on a water bill. Example: Minneapolis Water Works. Private wells are not in this inventory.

14%
of the state’s 967 active community water systems have a current result here
135
systems with a current nitrate result
2,721,305
people served by those reporting systems
29.6%
of reporting systems at or above 5 mg/L
How to read these numbers Each system is placed into a band by its most recent reported result within a rolling three-year window. The bands describe how strongly human activity, read from nitrate, has marked a water source; they are not a safety verdict. Figures describe system reporting, not nitrate measured at an individual tap.

How Minnesota's systems fall across the five bands

Most systems report below 3 mg/L

Natural background
0.00–0.99 mg/L as N
69 systems · 2,175,431 served
Human impact likely
1.00–2.99 mg/L as N
18 systems · 303,247 served
Human impact clear
3.00–4.99 mg/L as N
8 systems · 121,242 served
Health-study range
5.00–9.99 mg/L as N
40 systems · 121,385 served
Above the federal limit
10.00 mg/L and above
0 systems · 0 served

Each system appears in one band only, placed by its most recent reported result in the current three-year window. Counts sit beside people served so a small number of larger systems cannot hide behind a row of tiny ones. Of the 40 systems reporting 5 mg/L or more, not one of them stayed there across its whole three-year range — each reached 5 only on a high sample and otherwise ran lower.

Most recent reading Aug 2025; the typical system was last tested around Aug 2025. 79 systems sampled their own water; 56 systems carry a supplier’s result.

The named systems

Every reading here belongs to a utility with a name

Highest recent readings
SystemMost recent resultBandBased onPeople served
Hastings8.80 mg/La high point — runs lowerHealth-study rangeCCR summary, unverified23,222
Boyd7.50 mg/La high point — runs lowerHealth-study rangeinherited from supplier175
Hendricks7.50 mg/La high point — runs lowerHealth-study rangeinherited from supplier650
Ivanhoe7.50 mg/La high point — runs lowerHealth-study rangeinherited from supplier559
Lake Benton7.50 mg/La high point — runs lowerHealth-study rangeinherited from supplier676
Tyler7.50 mg/La high point — runs lowerHealth-study rangeinherited from supplier1,122
Verdi7.50 mg/La high point — runs lowerHealth-study rangeinherited from supplier32
Arco7.50 mg/La high point — runs lowerHealth-study rangeinherited from supplier74
Largest systems
SystemMost recent resultBandBased onPeople served
Minneapolis0.67 mg/LNatural backgroundCCR summary, unverified425,300
Saint Paul Regional Water Services0.15 mg/LNatural backgroundCCR summary, unverified392,529
Rochester0.19 mg/LNatural backgroundCCR summary, unverified123,624
Bloomington0.86 mg/LNatural backgroundCCR summary, unverified91,300
Brooklyn Park0.10 mg/LNatural backgroundCCR summary, unverified89,995

Each result shows its date and what it rests on, so a lone sample is never taken for a settled measurement. A single high sample is not a complete account of what a household drinks.

Where higher nitrate concentrates

Higher results gather in the southern and southwestern farm counties

Human impact is clear on drinking water served in 15 of Minnesota’s 87 counties. Each is shaded by how many of its systems reported 3.00 mg/L as N or above. Shading counts systems, not severity — a county with many small utilities can outrank one holding a single larger system that reads higher. The table beside the map splits the two bands so that difference stays visible.

MN counties shaded by number of community water systems reporting nitrate at or above 3.00 mg/L as NCounties are shaded by how many community water systems reported nitrate at or above 3.00 mg/L as N in the three years from August 9, 2023 to August 9, 2026. The same counts appear in the table below this map.Rock County — 0 systems at 3.00–4.99 mg/L as N; 2 systems at 5.00 mg/L as N or abovePipestone County — 0 systems at 3.00–4.99 mg/L as N; 6 systems at 5.00 mg/L as N or aboveRice County — 1 system at 3.00–4.99 mg/L as N; 0 systems at 5.00 mg/L as N or aboveNobles County — 0 systems at 3.00–4.99 mg/L as N; 8 systems at 5.00 mg/L as N or aboveLyon County — 0 systems at 3.00–4.99 mg/L as N; 7 systems at 5.00 mg/L as N or aboveLincoln County — 0 systems at 3.00–4.99 mg/L as N; 7 systems at 5.00 mg/L as N or aboveRedwood County — 0 systems at 3.00–4.99 mg/L as N; 2 systems at 5.00 mg/L as N or aboveLac qui Parle County — 0 systems at 3.00–4.99 mg/L as N; 1 system at 5.00 mg/L as N or aboveWashington County — 3 systems at 3.00–4.99 mg/L as N; 0 systems at 5.00 mg/L as N or aboveBlue Earth County — 1 system at 3.00–4.99 mg/L as N; 0 systems at 5.00 mg/L as N or aboveWabasha County — 1 system at 3.00–4.99 mg/L as N; 0 systems at 5.00 mg/L as N or aboveYellow Medicine County — 0 systems at 3.00–4.99 mg/L as N; 4 systems at 5.00 mg/L as N or aboveScott County — 1 system at 3.00–4.99 mg/L as N; 1 system at 5.00 mg/L as N or aboveDakota County — 0 systems at 3.00–4.99 mg/L as N; 2 systems at 5.00 mg/L as N or aboveSherburne County — 1 system at 3.00–4.99 mg/L as N; 0 systems at 5.00 mg/L as N or above
none1–23–56–1112–2526+Number of drinking water systems reporting ≥3.00 mg/L NO₃–N per county as of August 9, 2026

Nobles leads this layer with 8 reporting systems, followed by Lincoln, Lyon, Pipestone. Higher results gather in the southern and southwestern farm counties.

Counties with the most systems at or above 3 mg/L as N
County3–4.99≥5Total ≥3
Nobles088
Lincoln077
Lyon077
Pipestone066
Yellow Medicine044

Counts use each system's most recent reported result in the current three-year window. A system appears in only one of the two bands.

Find a specific Minnesota system

What the statewide pattern says

Fine till keeps most of the state low; two geologies concentrate the risk

Most of Minnesota is glaciated with fine till, where groundwater nitrate stays low. The risk concentrates where coarse sand or fractured carbonate lets surface nitrogen through — and the public-system map tracks the state's intensively farmed south.

Two Minnesota geologies do most of the work. The Central Sands — coarse, oxygen-rich glacial outwash under irrigated row crops and potatoes — let nitrate move down and persist, because there is too little oxygen-poor, carbon-rich material to break it down (Nolan and Hitt, 2006). The second is the southeastern karst, the creviced-carbonate country of the Driftless Area, where sinkholes and springs give surface nitrogen near-direct access to groundwater — the same belt as northeast Iowa and southwest Wisconsin.

The public-system map adds a third, data-first observation: the higher-band systems gather in the farm counties of the south and southwest — Nobles, Lincoln, Lyon and Pipestone among them — shallow glacial aquifers under intensive row crop and livestock. That is consistent with where the state's own monitoring concentrates: the Minnesota Department of Agriculture's Township Testing Program and Central Sands Private Well Network sample exactly these vulnerable farm regions, and find exceedances concentrated there rather than spread evenly across the state.

Elsewhere, the fine-till and tile-drained areas send their nitrate to surface water instead of down into wells, the familiar Corn Belt split. The supported source reading is agricultural — row-crop and livestock nitrogen on permeable or karst ground — not a certified source at any individual system. Underneath it all, the same slow travel times mean today's groundwater reflects yesterday's farming (Dubrovsky and others, 2010).

The general science — how nitrate moves, why some ground is vulnerable, and why the legacy lingers — is laid out with its sources on Where nitrate comes from.

Questions this page answers

What the Minnesota pattern does—and does not—say

Where does nitrate concentrate in Minnesota community water systems?

Nobles leads this layer with 8 reporting systems, followed by Lincoln, Lyon, Pipestone. Higher results gather in the southern and southwestern farm counties.

Which Minnesota landscapes carry the nitrate risk?

Two studied ones: the Central Sands, coarse oxic outwash under irrigated crops where nitrate persists, and the southeastern Driftless karst, where sinkholes give surface nitrogen direct access to groundwater. The public-system map also concentrates in the farmed south and southwest, where state township testing finds exceedances.

Can this page say the source is agriculture?

At the zone level, yes — carefully: row-crop and livestock nitrogen on permeable or karst ground. The evidence does not resolve fertilizer versus manure versus septic at each individual system.

Does a high public-system result mean a nearby private well is high?

No. It is a local sentinel, not a well-specific result. It shows that nitrogen and a transport pathway have reached groundwater in the area; a certified-lab test is still the only way to know a specific private well.

Sources and provenance

What this page rests on

  1. NitrateSmart inventory: 135 Minnesota community water systems with a current nitrate result in the three years from August 9, 2023 to August 9, 2026. Figures count people served by reporting systems, not measured tap exposure.
  2. Nolan BT, Hitt KJ (2006). Vulnerability of Shallow Groundwater and Drinking-Water Wells to Nitrate in the United States. Environmental Science & Technology 40(24):7834–7840.
  3. Dubrovsky NM, and others (2010). Nutrients in the Nation's Streams and Groundwater, 1992–2004. USGS Circular 1350.
  4. Minnesota Department of Agriculture — Township Testing Program, Central Sands Private Well Network, and Southeast Minnesota Volunteer Nitrate Monitoring Network reports — the state agency monitoring behind the claim that exceedance concentrates in vulnerable farm regions.