Markesan, WI: High Radon Risk — 65/100 (2026)
1 ZIP code · 1 water system · Updated 2026-06-03
Recent monitoring in Markesan shows middle-tier safety for WI — some systems are clean; others have logged EPA violations.
How Markesan Compares
Data: EPA SDWIS Last verified: 2026-06-03
Key Facts for Markesan Residents
- Average lead level: 0.0071 mg/L.
- Homes built before 1986: 74% — older plumbing may contain lead solder.
- Estimated remediation: $2,400 per household.
- CDC health risk index: 14.79 — above typical levels.
Markesan's Water Providers
One utility dominates residential water service in Markesan, WI — out of 1 system in federal records.
Overview
We track water quality and home safety data for 1 ZIP code in Markesan, Wisconsin, covering 1 community water system serving approximately 4,308 people.
No EPA violations recorded across any ZIP codes in Markesan — an excellent indicator of water quality.
Home Safety Score
Average Home Safety Score for Markesan: C (65/100)
The score combines three factors:
| Factor | What It Measures |
|---|---|
| Water Quality | EPA violations and compliance history |
| Lead Levels | 90th percentile lead concentration vs EPA action level |
| Radon Risk | EPA radon zone classification |
Water Sources
Markesan water systems draw from: Groundwater.
Lead & Copper
- Average lead level (90th percentile): 0.0071 mg/L (EPA action level: 0.015 mg/L)
- 0 ZIP codes exceed the EPA lead action level
Radon Risk
Dominant radon zone: Zone 1 (High Risk)
The EPA recommends testing homes in Zone 1 and Zone 2 areas for radon.
Areas with No Violations
| ZIP Code | Safety Score | System | Population |
|---|---|---|---|
| 53946 | C | Markesan Waterworks | 1,365 |
All ZIP Codes in Markesan
- 53946 [C]
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Lead/copper: EPA Lead and Copper Rule sampling data
- Radon: EPA Map of Radon Zones
Updated daily.
Markesan Community Health Snapshot
Source: CDC PLACES (County-level estimates). Water contamination can correlate with respiratory and chronic health conditions.
Compared to National Average
Vertical line = national average. ■ Above national · ■ Below national
Markesan Infrastructure Age
With 74% of homes built before 1986, lead solder in plumbing is a potential concern. The EPA banned lead solder in 1986, but many older homes retain original plumbing.
Source: U.S. Census Bureau American Community Survey (ACS).
Housing Age Profile
While newer cities carry lower aggregate plumbing risk from lead-era construction, Markesan sits firmly in the older category. The median build year of 1964 indicates that more than half the housing stock was built before 1986, when lead solder was still legally used in residential copper plumbing — and a substantial portion likely predates 1970, when lead pipes were still commonly installed for service lines. These two thresholds together define the elevated plumbing risk environment that older housing cities carry, independent of what the municipal water supply delivers to the meter.
Over half of homes in Markesan were built before 1986, when lead solder was banned. Older plumbing may leach lead into drinking water, especially with corrosive water chemistry.
Source: U.S. Census Bureau ACS B25034.
How Remediation Costs Compare in Markesan
Given current Markesan property values, the remediation share falls in the moderate tier — an indicator that the household financial perspective here calls for advance planning rather than dismissal, with most homeowners positioned to address documented issues through deliberate budgeting rather than needing to treat remediation as a significant equity event or financial emergency.
Remediation costs are moderate relative to home values in Markesan. The estimated $1,600–$3,300 range is manageable for most homeowners but still worth budgeting for. Home values are 1% above the Wisconsin average.
Markesan: Lead Risk & Vulnerable Populations
Why children are most at risk: The CDC states there is no safe level of lead exposure for children. Children under 6 absorb lead more readily than adults, and even low levels can cause developmental delays, learning difficulties, and behavioral problems.
Although utility-side compliance with federal Lead and Copper requirements remains the system reference, that compliance does not extend down into interior plumbing. With 74% of Markesan stock built before the solder ban and aggregate readings at or beyond the action mark, a household-level sample becomes the practical way to close that information gap.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
Markesan: Flood History & Water Damage Risk
Taken together, Markesan's 9 NFIP flood insurance claims and 100% FEMA flood zone coverage place it in the moderate range of exposure. That middle position has specific implications for water quality. The contamination pathways that flooding can open — surface water overwhelming treatment facility intake, floodwaters infiltrating private wells, distribution pressure changes creating backflow — are not constant risks in a moderate-exposure community. But they do become active during significant flood events, and the claim record here indicates enough of those events to make flood timing an occasional factor in local water quality conversations.
Markesan has a moderate flood history with 9 FEMA claims averaging $8,563 per payout. 100% of ZIP codes fall within FEMA flood zones. Flood events can contaminate drinking water and overwhelm treatment systems.
How flooding affects water quality: Flood events can introduce sewage, agricultural runoff, and industrial chemicals into water supplies. Even after floodwaters recede, contamination can persist in wells and aging infrastructure. Flood damage can add significantly to the estimated <strong>$2,400</strong> remediation cost per household.
Residents in flood-prone areas should consider flood insurance even outside FEMA zones — over 25% of flood claims come from low-to-moderate risk areas. After any flood event, test your water before drinking.
Source: FEMA National Flood Insurance Program (NFIP) claims data, FEMA flood zone designations.
What You Can Do in Markesan
- Test your water at home. City-level data shows averages — your tap may differ. NSF-certified test kits cost $20-40 and give results in days.
- Install a certified water filter. An NSF-certified pitcher or under-sink filter removes most common contaminants.
- Check your home's plumbing. With 74% of homes built before 1986, lead solder is a real possibility.
Deep Dive Reports
Detailed analysis for Markesan, WI