Is Mahnomen, MN Tap Water Safe to Drink?
Graded A, with 1 unresolved violation on record. See what was cited — and what it means for your tap. What to do next ↓
91.6/100
waterverge.com Mahnomen, MN — Water Quality Report
Mahnomen's drinking water received a grade of A (91.6 out of 100), indicating excellent water quality. The city's 1 water system serves approximately 1,210 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.
The system has 3 violations on record, including 0 health-based violations. 1 remains unresolved.
What to know about Mahnomen's water
Mahnomen ranks #160 out of 466 cities in Minnesota for water quality, placing it mid-range in the state.
Mahnomen 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, Mahnomen may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
Water quality score
See methodology →Is Mahnomen, MN water safe to drink?
Mahnomen's tap water meets most EPA standards but has areas that warrant attention. With a grade of A (91.6/100), some contaminant levels or compliance issues suggest that residents may benefit from additional filtration. The city's 1 water system serves approximately 1,210 residents using groundwater (wells).
Recent water quality updates for Mahnomen
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Mahnomen's water quality assessment. Grade: A (91.6/100).
Federal disaster declaration (FEMA DR-4722). Flood event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-4659). Flood event — may have impacted local water infrastructure.
Contaminants: Coliform (TCR).
Contaminants: Coliform (TCR).
Key contaminant findings
Based on the most recent EPA sampling data for Mahnomen's water supply.
Well within EPA limits.
Violation history
Mahnomen's water system has 3 total violations on record, including 0 health-based violations. 1 remain unresolved.
Flood & environmental risk
Mahnomen County has experienced 9 federally declared disasters since 1965. Flooding and severe storms can overwhelm water treatment plants, cause sewage overflows, and introduce agricultural runoff, bacteria, and sediment into drinking water supplies.
Where does Mahnomen's water come from?
Mahnomen's drinking water comes from groundwater (wells), supplied by 1 water system serving approximately 1,210 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate.
What Mahnomen residents can do
Your water utility is required to publish an annual Consumer Confidence Report (CCR) with detailed testing results. Ask for the latest copy or check your utility's website.
Mahnomen's area has a history of flooding. After severe weather, watch for boil water advisories from your local utility.
Data: EPA SDWIS, UCMR 5 (PFAS), FEMA, NOAA. Last updated May 2026.
Top contaminants to know
View all ↓Violation summary
Violations & advisories
Flood & disaster history
Mahnomen County has experienced 9 federally declared disasters since 1965. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
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 |
Lead level (90th percentile)
Latest reading: 0.0 ppb (2023)
EPA action level: 15 ppb
See how Mahnomen compares by contaminant
Explore where Mahnomen ranks among all Minnesota cities for specific contaminants.
Water source & infrastructure
Where Mahnomen's water comes from
Mahnomen's drinking water is drawn from underground aquifers through wells.
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 1,210 people through 1 water system.
Water systems serving Mahnomen
| System Name | PWSID | Population | Source |
|---|---|---|---|
| Mahnomen | MN1440002 | 1,210 | GW |
How Mahnomen compares
Full Minnesota rankings →Mahnomen's score of 91.6/100 is above the average of 82/100 among major Minnesota cities. It outscores 9 of 10 nearby cities.
Nearby cities
View Minnesota rankings →About Mahnomen, MN
Learn more about your water
Guides and resources related to Mahnomen's water quality findings.
Explore water quality across Mahnomen
Frequently asked questions
Is Mahnomen, MN tap water safe to drink?
Mahnomen's water quality earned a grade of A (91.6/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #160 out of 466 cities tested in Minnesota.
What contaminants are in Mahnomen's water?
Lead was measured at 0.0 ppb (90th percentile). 3 violations are on record.
How is Mahnomen'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 Mahnomen?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Mahnomen's water come from?
Mahnomen's water is sourced from Groundwater. The city has 1 water system serving approximately 1,210 residents.
Is Mahnomen's groundwater at risk of contamination?
Mahnomen 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 3 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 Mahnomen's water compare to other cities?
Mahnomen ranks #160 out of 466 cities in Minnesota (better than 66% of state cities) and #1602 out of 15744 cities nationally (90th percentile). The grade of A reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Mahnomen's small water system affect quality?
Mahnomen's system serves approximately 1,210 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 3 violations on record.