Is Markesan, WI Tap Water Safe to Drink?
Graded B+, with 1 unresolved violation on record. See what was cited — and what it means for your tap. What to do next ↓
82.7/100
waterverge.com Markesan, WI — Water Quality Report
Markesan's drinking water received a grade of B+ (82.7 out of 100), indicating good water quality. The city's 1 water system serves approximately 1,365 residents using groundwater.
Lead levels were measured at 7.1 ppb (90th percentile), which is within EPA limits but above recommended levels. This system has not yet been tested for PFAS under the EPA UCMR 5 program.
The system has 1 violation on record, including 0 health-based violations. 1 remains unresolved.
What to know about Markesan's water
Markesan ranks #214 out of 446 cities in Wisconsin for water quality, placing it mid-range in the state.
Markesan 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.
While lead levels are within EPA limits, they are above the recommended 5 ppb threshold that health organizations consider ideal. A point-of-use filter adds an extra layer of protection.
As a small community water system, Markesan may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
Water quality score
See methodology →Is Markesan, WI water safe to drink?
Markesan's tap water meets most EPA standards but has areas that warrant attention. With a grade of B+ (82.7/100), some contaminant levels or compliance issues suggest that residents may benefit from additional filtration. The city's 1 water system serves approximately 1,365 residents using groundwater (wells).
Recent water quality updates for Markesan
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Markesan's water quality assessment. Grade: B+ (82.7/100).
Federal disaster declaration (FEMA DR-4402). Flood event — may have impacted local water infrastructure.
Federal disaster declaration (FEMA DR-3249). Hurricane event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for Markesan's water supply.
Within EPA limits but above the American Academy of Pediatrics recommended level of 1 ppb. An NSF 53-certified filter provides additional protection.
Violation history
Markesan's water system has 1 total violation on record, including 0 health-based violations. 1 remain unresolved.
Flood & environmental risk
Green Lake County has experienced 3 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 Fox River, Wuerches Creek, Roy Creek, Green Lake Sw Inlet @ Ct Highwy K Nr Green Lake,Wi, White Creek.
Where does Markesan's water come from?
Markesan's drinking water comes from groundwater (wells), supplied by 1 water system serving approximately 1,365 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Fox River (river), Wuerches Creek (river), Roy Creek (river), Green Lake Sw Inlet @ Ct Highwy K Nr Green Lake,Wi (river), White Creek (river).
What Markesan 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.
Run cold water for 30 seconds before drinking, especially in the morning. Lead and copper leach from household plumbing when water sits in pipes.
Markesan'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
Top industrial polluters within 10 miles of Markesan
Industrial polluters nearby
Reported releases to surface water by facilities near Markesan, ranked by pounds discharged annually.
| Facility | Top chemical | To surface water (lbs/yr) | Distance |
|---|---|---|---|
SIGMA ENGINEERED SOLUTIONS MARKESAN, WI53946 | — | — | 0.7 mi |
Source: EPA Toxic Release Inventory (TRI) 2023
Flood & disaster history
Green Lake County has experienced 3 federally declared disasters since 1973. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
Recommended water filters
Based on contaminants detected in Markesan's water supply, we recommend the following filter types.
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. | 7.1 | 15 | ppb | Inorganic | Safe |
Lead level trend (90th percentile)
See how Markesan compares by contaminant
Explore where Markesan ranks among all Wisconsin cities for specific contaminants.
Water source & infrastructure
Where Markesan's water comes from
Markesan'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 1,365 people through 1 water system.
Water bodies near Markesan
Markesan is located near 5 notable water bodies. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Markesan
| System Name | PWSID | Population | Source |
|---|---|---|---|
| MARKESAN WATERWORKS | WI4240218 | 1,365 | GW |
How Markesan compares
Full Wisconsin rankings →Markesan's score of 82.7/100 is above the average of 65/100 among major Wisconsin cities. It outscores 7 of 10 nearby cities.
Nearby cities
View Wisconsin rankings →About Markesan, WI
Learn more about your water
Guides and resources related to Markesan's water quality findings.
Explore water quality across Green Lake
Frequently asked questions
Is Markesan, WI tap water safe to drink?
Markesan's water quality earned a grade of B+ (82.7/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #214 out of 446 cities tested in Wisconsin.
What contaminants are in Markesan's water?
Lead was measured at 7.1 ppb (90th percentile). 1 violation is on record.
How is Markesan'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 Markesan?
While lead levels are within EPA limits, a filter adds extra protection. Based on current data, basic filtration should suffice for additional peace of mind.
Where does Markesan's water come from?
Markesan's water is sourced from Groundwater. The city has 1 water system serving approximately 1,365 residents.
Is Markesan's groundwater at risk of contamination?
Markesan 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 1 violation 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 Markesan's water compare to other cities?
Markesan ranks #214 out of 446 cities in Wisconsin (better than 52% of state cities) and #6829 out of 15744 cities nationally (57th percentile). The grade of B+ reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Markesan's small water system affect quality?
Markesan's system serves approximately 1,365 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 1 violation on record.