Markesan Waterworks
EPA ID: WI4240218 · 1,365 people served · 2 ZIP codes
Federal monitoring records confirm Markesan Waterworks has operated without any EPA violations for the full five-year window — covering every contaminant category and reporting cycle across a service area of approximately 1,365 residents, with no gaps in the compliance record.
Data: EPA SDWIS Last verified: 2026-04-02
Service Area Map
Coverage area for Markesan Waterworks Source: EPA SDWIS service area boundaries.
Service area boundary — Grade D
Service Area Demographics
The Markesan Waterworks serves a community with a median household income of $68,500 and an estimated 4,577 residents across its service area. Approximately 78% of housing stock was built before 1986, which increases the likelihood of lead service lines and older plumbing.
💧 Where Does Your Water Come From?
Markesan Waterworks's water is pumped from underground aquifers. Groundwater is naturally filtered through rock and soil, but it can be vulnerable to PFAS contamination, nitrates from agriculture, and industrial chemicals that seep into the water table.
About 2% of homes in Green Lake County, Wisconsin rely on private wells rather than public water systems. Private well owners are responsible for their own water testing and treatment.
Infrastructure Risk
Comparable Water Systems
Similar-sized systems in Wisconsin
Estimated Remediation Costs
Average estimated costs across ZIP codes served by this system
Based on national averages for common remediation projects. Actual costs vary by property. Only issues flagged by EPA, FEMA, or state data for each ZIP code are included.
System Overview
MARKESAN WATERWORKS (EPA ID: WI4240218) is a community water system in Wisconsin that serves approximately 1,365 people from groundwater sources.
This system provides water to 2 ZIP codes across 2 communities.
Average Home Safety Score: D (53/100)
Based on water quality violations, lead levels, and radon risk across all ZIP codes served by this system.
Violation History
Lead & Copper
EPA Lead and Copper Rule sampling data for ZIP codes served by this system:
| ZIP Code | Lead Level | Exceeds Limit | Sample Date |
|---|---|---|---|
| 53946 | 0.0071 mg/L | No | N/A |
Radon Risk in Service Area
Dominant radon zone for ZIP codes served by this system: Zone 1 (High Risk)
The EPA recommends testing homes in Zone 1 and Zone 2 areas for radon.
Need help with your water quality?
Typical cost: Water test: typically $20–$50 (DIY kit) · Professional inspection: $150–$400
Find the Right Water FilterFree tip: Let cold water run for 2 minutes before drinking — this helps flush lead from your pipes.
ZIP Codes Served
Coverage: 1 ZIP code confirmed via EPA Community Water System Service Area Boundaries v3 plus 1 additional ZIP inferred from SDWIS registry data. The EPA-confirmed set is the most reliable; SDWIS-inferred entries may be narrower than the real deployment area.
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View the full compliance record for Markesan Waterworks (WI4240218) on EPA.gov.
Frequently Asked Questions
Is Markesan Waterworks water safe to drink?
Based on EPA records, Markesan Waterworks has no recorded violations in the past 5 years — a positive indicator of water quality management.
How many people does Markesan Waterworks serve?
Markesan Waterworks serves approximately 1,365 people across 2 ZIP codes in Wisconsin.
Where does Markesan Waterworks get its water?
The primary water source is groundwater.
Lead Service Line Inventory
Service line breakdown reported under the federal Lead and Copper Rule Improvements (LCRI) inventory requirement:
Federal LCRI rule (effective October 2024) requires every public water system to inventory its service lines and complete lead-line replacement within 10 years.
Source: EPA SDWIS Federal Service Line Inventory (Phase 2) · Submitted 2026
ZipCheckup is not affiliated with the utility or state agency. Inventory figures render verbatim from the public LCRI submission cited above; ZipCheckup does not perform inspections or replacements.
Frequently Asked Questions
What You Can Do
Test your water
Home test kits can detect lead, bacteria, and other contaminants at your tap. Find the right filter →
Check your specific ZIP code
Water quality can vary within a system. View nearest ZIP report →
Contact your utility
Markesan Waterworks (EPA ID: WI4240218) — request the latest Consumer Confidence Report or ask about specific contaminants.