01The verdict: is Clarks Grove water safe?
Based on EPA testing data, Clarks Grove's tap water is generally safe to drink. The water system earned a grade of A (93/100), meeting federal drinking water standards across key contaminant categories. The city's 1 water system serves approximately 695 residents using groundwater (wells).
Copper is over its legal limit
Measured at 1.57 mg/L against the EPA Action Level of 1.3 mg/L. The ledger below shows how far over — and which filter removes it.
See the measurement ↓A clean compliance record
Clarks Grove has no EPA violations on file — a stronger record than most systems its size.
See the record ↓A flood-prone service area
9 federal disaster declarations on record. After severe weather, watch for boil-water advisories.
See the risk factors ↓Clarks Grove's drinking water received a grade of A (93 out of 100), indicating excellent water quality. The city's 1 water system serves approximately 695 residents using groundwater.
Lead levels were measured at 0.0 ppb (90th percentile), well within EPA limits. This system has not yet been tested for PFAS under the EPA UCMR 5 program. No violations are on record for this water system.
Clarks Grove ranks #115 out of 466 cities in Minnesota for water quality, placing it above average in the state. Clarks Grove 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, Clarks Grove may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities. Clarks Grove has a clean compliance record with no violations on file, reflecting strong operational practices.
02What's in Clarks Grove's water
Every contaminant flagged in Clarks Grove, 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.
Over Limit — EPA Action Level: 1.3 mg/L
Exceeds the EPA action level. Copper leaches from household plumbing — flush taps for 30 seconds before drinking, and consider a certified filter.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. | 0.0 | 15 | ppb | Inorganic | Safe |
| Copper (90th percentile) CopperInorganic A metal that enters drinking water mainly through corrosion of copper plumbing. Small amounts are essential for health, but excess levels are harmful. Health EffectsGastrointestinal distress (nausea, vomiting, diarrhea) at short-term high levels; liver and kidney damage from long-term exposure. EPA Limit1.3 mg/L action level Common SourcesCorrosion of copper household plumbing, erosion of natural deposits. | 1.57 | 1.3 | mg/L | Inorganic | Over Limit |
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
03Clarks Grove'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. No violations are on record for this water system.
All ten of the last ten years were clean — no EPA violations recorded for Clarks Grove.
▼ Down 3 ppb since 2012. Latest reading: 0 ppb (2025) — 0% of the action level. Sampled at higher-risk homes (90th percentile).
▼ Down 0.66 mg/L since 2011. The latest reading (1.6 mg/L, 2022) is over the action level. Sampled at higher-risk homes (90th percentile).
04Where Clarks Grove's water comes from
Clarks Grove'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.
695 people
Residents served across Clarks Grove'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 695 people through 1 water system.
| System name | PWSID | Population | Source |
|---|---|---|---|
| Clarks Grove | MN1240005 | 695 | Groundwater |
05Pressure on Clarks Grove'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
3 facilities within 10 miles reported 0 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
9 federal disaster declarations on record for Freeborn County. Flooding and severe storms can overwhelm treatment plants, cause sewage overflows, and push runoff into supplies.
Drought
Freeborn County is in D1 (moderate drought) per the U.S. Drought Monitor (week of Jul 2026). Drought can raise disinfection-byproduct levels and taste/odor issues as utilities draw from lower reservoirs.
06How Clarks Grove compares
Scores for nearby Minnesota cities on one line, with the average marked.
dashed line = Minnesota average (82/100)
Clarks Grove scores 93/100 — above the Minnesota average of 82/100. It outscores 9 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 Clarks Grove's water — not generic advice.
Filter drinking & cooking water
Basic carbon filter for extra protection. Copper exceeds the EPA action level of 1.3 mg/L
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 Clarks Grove 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 Clarks Grove, MN tap water safe to drink?
Clarks Grove's water quality earned a grade of A (93/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #115 out of 466 cities tested in Minnesota.
What contaminants are in Clarks Grove's water?
Lead was measured at 0.0 ppb (90th percentile). No violations on record.
How is Clarks Grove'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 Clarks Grove?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Clarks Grove's water come from?
Clarks Grove's water is sourced from Groundwater. The city has 1 water system serving approximately 695 residents.
Is Clarks Grove's groundwater at risk of contamination?
Clarks Grove uses groundwater, which can be affected by naturally occurring contaminants like arsenic, radon, and nitrate, as well as agricultural runoff and industrial activity. Current testing shows the groundwater meets EPA standards. Groundwater systems are generally less susceptible to surface contamination but should be monitored for emerging contaminants like PFAS.
How does Clarks Grove's water compare to other cities?
Clarks Grove ranks #115 out of 466 cities in Minnesota (better than 75% of state cities) and #1030 out of 15382 cities nationally (93th percentile). The grade of A reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Clarks Grove's small water system affect quality?
Clarks Grove's system serves approximately 695 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 maintained a clean compliance record.