Is Marathon City, WI Tap Water Safe to Drink?
Graded B, with 7 unresolved violations on record. See what was cited — and what it means for your tap. What to do next ↓
78.7/100
waterverge.com Marathon City, WI — Water Quality Report
Marathon City's drinking water received a grade of B (78.7 out of 100), indicating good water quality. The city's 1 water system serves approximately 1,695 residents using groundwater.
Lead levels were measured at 0.4 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 11 violations on record, including 2 health-based violations. 7 remain unresolved.
What to know about Marathon City's water
Marathon City ranks #280 out of 446 cities in Wisconsin for water quality, placing it below average in the state.
Marathon City 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, Marathon City may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
Water quality score
See methodology →Is Marathon City, WI water safe to drink?
Marathon City's drinking water has significant quality concerns based on EPA testing data. With a grade of B (78.7/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 1 water system serves approximately 1,695 residents using groundwater (wells).
Recent water quality updates for Marathon City
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Marathon City's water quality assessment. Grade: B (78.7/100).
1 health-based. Contaminants: LEAD AND COPPER RULE REVISIONS, Public Notice.
Contaminants: Lead and Copper Rule.
Contaminants: Total Haloacetic Acids (HAA5), TTHM.
Federal disaster declaration (FEMA DR-3249). Hurricane event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-376). Flood event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for Marathon City's water supply.
Well within EPA limits.
Violation history
Marathon City's water system has 11 total violations on record, including 2 health-based violations. 7 remain unresolved. 3 violations were issued in the last 5 years.
Flood & environmental risk
Marathon County has experienced 2 federally declared disasters since 1973. Flooding and severe storms can overwhelm water treatment plants, cause sewage overflows, and introduce agricultural runoff, bacteria, and sediment into drinking water supplies. Local water sources include Big Rib River, Wisconsin River.
Where does Marathon City's water come from?
Marathon City's drinking water comes from groundwater (wells), supplied by 1 water system serving approximately 1,695 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Big Rib River (river), Wisconsin River (river).
What Marathon City residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Marathon City's water.
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.
Data: EPA SDWIS, UCMR 5 (PFAS), FEMA, NOAA. Last updated May 2026.
Top contaminants to know
View all ↓Violation summary
Violations & advisories
Top industrial polluters within 10 miles of Marathon City
Industrial polluters nearby
Reported releases to surface water by facilities near Marathon City, ranked by pounds discharged annually.
| Facility | Top chemical | To surface water (lbs/yr) | Distance |
|---|---|---|---|
VERITAS STEEL WAUSAU, WI54401 | — | — | 8.4 mi |
LINETEC PAINT/PLASTICS WAUSAU, WI54401 | — | — | 6.0 mi |
HARTLAND LUBRICANTS & CHEMICALS-WAUSAU WAUSAU, WI54401 | — | — | 6.5 mi |
WAUSAU CHEMICAL CORP WAUSAU, WI54401 | — | — | 4.4 mi |
Source: EPA Toxic Release Inventory (TRI) 2023
Flood & disaster history
Marathon County has experienced 2 federally declared disasters since 1973. 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. | 0.4 | 15 | ppb | Inorganic | Safe |
Lead level trend (90th percentile)
See how Marathon City compares by contaminant
Explore where Marathon City ranks among all Wisconsin cities for specific contaminants.
Water source & infrastructure
Where Marathon City's water comes from
Marathon City'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 1,695 people through 1 water system.
Water bodies near Marathon City
Marathon City is located near 2 notable water bodies. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Marathon City
| System Name | PWSID | Population | Source |
|---|---|---|---|
| MARATHON CITY WATERWORKS | WI7370151 | 1,695 | GW |
How Marathon City compares
Full Wisconsin rankings →Marathon City's score of 78.7/100 is above the average of 65/100 among major Wisconsin cities. It outscores 6 of 10 nearby cities.
Nearby cities
View Wisconsin rankings →About Marathon City, WI
Learn more about your water
Guides and resources related to Marathon City's water quality findings.
Explore water quality across Marathon
Frequently asked questions
Is Marathon City, WI tap water safe to drink?
Marathon City's water quality earned a grade of B (78.7/100). Some concerns have been identified. Consider a water filter for an extra layer of protection. The city ranks #280 out of 446 cities tested in Wisconsin.
What contaminants are in Marathon City's water?
Lead was measured at 0.4 ppb (90th percentile). 11 violations are on record.
How is Marathon City'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 Marathon City?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Marathon City's water come from?
Marathon City's water is sourced from Groundwater. The city has 1 water system serving approximately 1,695 residents.
What health violations has Marathon City's water system had?
Marathon City has 2 health-based violations 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. 7 violations remain unresolved.
Is Marathon City's groundwater at risk of contamination?
Marathon City 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 11 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 Marathon City's water compare to other cities?
Marathon City ranks #280 out of 446 cities in Wisconsin (better than 37% of state cities) and #8571 out of 15744 cities nationally (46th percentile). The grade of B reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Marathon City's small water system affect quality?
Marathon City's system serves approximately 1,695 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 11 violations on record.