01The verdict: is Winthrop water safe?
Winthrop's drinking water has significant quality concerns based on EPA testing data. With a grade of B+ (81.1/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 1 water system serves approximately 1,330 residents using groundwater (wells).
3 unresolved violations on record
EPA records show open compliance items for this system. Most are administrative, but unresolved items are worth watching.
See what was cited ↓Lead is well under the limit
90th-percentile lead is 3.0 ppb — beneath the 15 ppb federal action level and under the 5 ppb watch threshold.
See the trend ↓2 violations in the last five years
Recent compliance history is the best predictor of future problems — the year-by-year record is below.
See the record ↓Winthrop's drinking water received a grade of B+ (81.1 out of 100), indicating good water quality. The city's 1 water system serves approximately 1,330 residents using groundwater.
Lead levels were measured at 3.0 ppb (90th percentile), well within EPA limits. This system has not yet been tested for PFAS under the EPA UCMR 5 program. The system has 4 violations on record, including 1 health-based violation. 3 remain unresolved.
Winthrop ranks #410 out of 466 cities in Minnesota for water quality, placing it among the lowest-rated in the state. Winthrop relies on groundwater, which is generally less vulnerable to surface contamination but can be affected by naturally occurring minerals like arsenic and nitrate, as well as agricultural and industrial runoff. As a small community water system, Winthrop may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
02What's in Winthrop's water
Every contaminant flagged in Winthrop, on one shared scale: distance to its own legal limit. The red line is the limit — anything past it is out of compliance, and the closer a bar gets, the less headroom the system has.
Full contaminants report
| Contaminant | Detected Level | EPA Limit | Unit | Category | Status |
|---|---|---|---|---|---|
| Lead (90th percentile) LeadHeavy Metal A toxic heavy metal that can leach into drinking water from older pipes, solder, and fixtures. No amount of lead in water is considered safe. Health EffectsBrain and nervous system damage in children, kidney damage, high blood pressure, and reproductive problems in adults. EPA Limit15 ppb action level Common SourcesCorrosion of lead pipes, lead solder, brass faucets, and household plumbing. | 3.0 | 15 | ppb | Inorganic | Safe |
Cities ranked by 90th-percentile lead PF PFAS in Minnesota
Cities ranked by compounds detected Cu Copper in Minnesota
Cities ranked by 90th-percentile copper
03Winthrop's ten-year track record
Each box is one year. A green check means no EPA violations; a numbered badge counts that year's violations — red if any were health-based, amber if they were monitoring or paperwork issues. The system has 4 violations on record, including 1 health-based violation. 3 remain unresolved.
9 of the last ten years were clean. The numbered years had EPA violations — red when any were health-based, amber when they were paperwork or missed-testing issues.
3ppb(2023)
One sampling round on record — 20% of the 15ppb EPA action level. Sampled at higher-risk homes (90th percentile).
04Where Winthrop's water comes from
Winthrop's drinking water is drawn from underground aquifers through wells.
Groundwater
Underground aquifers reached by wells — naturally filtered, but can carry minerals like arsenic and nitrate.
Local treatment
Groundwater generally needs less treatment — typically disinfection and, where needed, mineral removal.
1 system
1 water system, operated under local government ownership.
1,330 people
Residents served across Winthrop's service area.
Groundwater is naturally filtered through rock and soil layers, generally requiring less treatment than surface water. However, it can contain naturally occurring contaminants like arsenic, radon, and minerals. Agricultural activity, septic systems, and industrial operations near well fields can introduce nitrates, pesticides, and volatile organic compounds. The system is operated by local government ownership and serves approximately 1,330 people through 1 water system.
| System name | PWSID | Population | Source |
|---|---|---|---|
| Winthrop | MN1720008 | 1,330 | Groundwater |
05Pressure on Winthrop's watershed
Outside forces that shape what reaches the treatment plant. None of these is a verdict on the tap by itself — but each adds pressure worth knowing about.
Industrial discharge
4 facilities within 10 miles reported 88k lb released to surface water in the latest EPA Toxics Release Inventory. Proximity doesn't equal tap contamination — treatment and hydrology decide — but it's pressure on the watershed.
Flood & storm history
10 federal disaster declarations on record for Sibley County. Flooding and severe storms can overwhelm treatment plants, cause sewage overflows, and push runoff into supplies.
06How Winthrop compares
Scores for nearby Minnesota cities on one line, with the average marked.
dashed line = Minnesota average (82/100)
Winthrop scores 81.1/100 — on par with the Minnesota average of 82/100. It outscores 4 of 10 nearby cities. Full Minnesota rankings →
72.8 / 100BSt. Paul, MN
73.3 / 100CRochester, MN
69.7 / 100ABloomington, MN
93.6 / 100BBrooklyn Park, MN
81.5 / 100ADuluth, MN
88.6 / 100
Compare all cities in the county — grades, violations, and contaminant data side by side.→
07What to do at home
Steps matched to what testing actually found in Winthrop's water — not generic advice.
A basic carbon filter still helps
Winthrop's water meets federal standards, but a simple carbon filter improves taste and adds a margin of safety against short-term issues.
Compare tested filters →Read your utility's annual report
Every utility must publish a yearly Consumer Confidence Report with its own testing results. It pairs well with the independent data on this page.
How to read a CCR →Watch for Winthrop alerts
This area has a history of flood declarations — after severe weather, watch for boil-water advisories from the utility, and check the live alerts on this page.
All water alerts →Frequently asked questions
Is Winthrop, MN tap water safe to drink?
Winthrop's water quality earned a grade of B+ (81.1/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #410 out of 466 cities tested in Minnesota.
What contaminants are in Winthrop's water?
Lead was measured at 3.0 ppb (90th percentile). 4 violations are on record.
How is Winthrop's water quality grade calculated?
The grade is based on four factors: violation history (40%), lead and copper levels (25%), PFAS contamination (25%), and regulatory compliance (10%). The score is also adjusted based on how complete the available data is. See our methodology page for full details.
Do I need a water filter in Winthrop?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Winthrop's water come from?
Winthrop's water is sourced from Groundwater. The city has 1 water system serving approximately 1,330 residents.
What health violations has Winthrop's water system had?
Winthrop has 1 health-based violation on record. The most recent violation was recorded in October 2024. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 3 violations remain unresolved.
Is Winthrop's groundwater at risk of contamination?
Winthrop uses groundwater, which can be affected by naturally occurring contaminants like arsenic, radon, and nitrate, as well as agricultural runoff and industrial activity. The system has 4 violations on record that may relate to groundwater quality. Groundwater systems are generally less susceptible to surface contamination but should be monitored for emerging contaminants like PFAS.
How does Winthrop's water compare to other cities?
Winthrop ranks #410 out of 466 cities in Minnesota (better than 12% of state cities) and #7506 out of 15382 cities nationally (51th percentile). The grade of B+ reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Winthrop's small water system affect quality?
Winthrop's system serves approximately 1,330 residents. Small community water systems (under 3,300 people) may have fewer financial resources for infrastructure upgrades and advanced treatment technologies. However, they are held to the same EPA drinking water standards as larger systems. This system has 4 violations on record.