Colby, WI: High Radon Risk — 66/100 (2026)
1 ZIP code · 5 water systems · Updated 2026-06-03
Compliance figures for Colby indicate average water quality in WI overall — some service areas have recorded health-based violations in recent monitoring cycles, while others operate cleanly, making system-level data the most actionable reference point for residents.
How Colby Compares
Data: EPA SDWIS Last verified: 2026-06-03
What You Should Know About Colby Water
- Average lead level: 0.0009 mg/L.
- Homes built before 1986: 71% — older plumbing may contain lead solder.
- Estimated remediation: $1,200 per household.
- CDC health risk index: 12.89 — above typical levels.
Who Supplies Your Water in Colby
Structurally, Colby, WI's water supply is divided. Federal data identifies 5 water systems in the area, with 3 providers serving the bulk of residential connections. These utilities operate independently, meaning rate-setting authority and EPA compliance accountability are distributed rather than centralized.
Overview
We track water quality and home safety data for 1 ZIP code in Colby, Wisconsin (population ~3,724), covering 5 community water systems serving approximately 6,611 people region-wide.
No EPA violations recorded across any ZIP codes in Colby — an excellent indicator of water quality.
Home Safety Score
Average Home Safety Score for Colby: C (66/100)
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
Colby water systems draw from: Groundwater.
Lead & Copper
- Average lead level (90th percentile): 0.0009 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 |
|---|---|---|---|
| 54421 | C | Colby Waterworks | 1,829 |
All ZIP Codes in Colby
- 54421 [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.
Health Outcomes in Colby
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
Housing & Infrastructure in Colby
With 71% 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
Because the majority of Colby's housing predates 1986, when lead solder was banned from new plumbing, the median build year of 1978 reflects a city where lead-era plumbing materials are common rather than exceptional.
Over half of homes in Colby 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.
Cost Context: What Remediation Means for Colby Homeowners
In Colby, property wealth outpaces what documented remediation typically demands — the equity burden lands well within the low tier.
Remediation costs in Colby are relatively low compared to home values. The $800–$1,500 estimated range is a small fraction of median property value. Home values are 23% below the Wisconsin average.
Lead Exposure Risk for Children in Colby
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.
Routinely in Colby, where 71% of housing predates the solder ban and aggregate utility readings hover near the federal threshold, a faucet-level draw functions as a standard household step for families with small kids.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
What You Can Do in Colby
- 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 71% of homes built before 1986, lead solder is a real possibility.
Deep Dive Reports
Detailed analysis for Colby, WI