Defiance, MO: 22 Health Violations — 53/100 (2026)
1 ZIP code · 2 water systems · Updated 2026-06-03
Within Defiance, water quality data indicates below-average safety by MO standards — independent testing is a reasonable precaution for residents whose systems show active violations.
How Defiance Compares
Data: EPA SDWIS Last verified: 2026-06-03
Defiance Water: The Quick Version
- Your city's water systems recorded 38 violations in the past 5 years.
- Average lead level: 0.0021 mg/L.
- Homes built before 1986: 37% — older plumbing may contain lead solder.
- Estimated remediation: $2,700 per household.
- CDC health risk index: 13.6 — above typical levels.
Water Systems Serving Defiance
With 2 utilities splitting service in Defiance, MO, water accountability is distributed across 2 systems on the federal record.
Overview
We track water quality and home safety data for 1 ZIP code in Defiance, Missouri (population ~3,554), covering 2 community water systems serving approximately 100,697 people region-wide.
1 of 1 ZIP code (100%) have recorded EPA violations. 22 health-based violations documented.
Home Safety Score
Average Home Safety Score for Defiance: D (53/100)
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
Defiance water systems draw from: Groundwater.
Lead & Copper
- Average lead level (90th percentile): 0.0021 mg/L (EPA action level: 0.015 mg/L)
- 0 ZIP codes exceed the EPA lead action level
Radon Risk
Dominant radon zone: Zone 2 (Moderate Risk)
The EPA recommends testing homes in Zone 1 and Zone 2 areas for radon.
Top Contaminants
| Contaminant | Category | Violations | ZIPs Affected |
|---|---|---|---|
| Gross Beta | Radionuclides | 34 | 1 |
| Lead and Copper Rule | Treatment Technique | 24 | 1 |
| Consumer Confidence Report Rule | Reporting | 10 | 1 |
| Contaminant 0700 | Other | 4 | 1 |
| Stage 2 DBP Rule | Treatment Technique | 2 | 1 |
Areas with Most Violations
| ZIP Code | Safety Score | Violations | Health-Based | System |
|---|---|---|---|---|
| 63341 | D | 38 | 22 | St Charles County Pwsd 2 |
All ZIP Codes in Defiance
- 63341 [D] — 38 violations ⚠
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.
CDC Health Data for Defiance
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
Key Contaminants Detected in Defiance
Based on EPA violation records. Check your ZIP code report for system-specific contaminant data.
How Old Is Defiance's Housing Stock?
Housing age data helps assess potential lead pipe and infrastructure risks. Newer housing stock generally means lower plumbing-related contamination risk.
Source: U.S. Census Bureau American Community Survey (ACS).
Housing Age Profile
Because Defiance's housing stock spans a wide range of construction eras, the median build year of 1997 lands in a zone where two distinct risk populations share the same residential market. Homes built before 1986 may have lead-soldered copper plumbing joints — that practice was federally prohibited in 1986 but remained standard until then. The fraction built before 1970 face an additional risk: lead pipes used for service line connections were common before that decade, meaning both the pipe and the solder may be lead-containing in the oldest structures. Residents in mid-century or earlier homes face a different risk environment than neighbors in houses built after 1986, even if they drink from the same utility's supply — and that property-level divergence is what makes the age distribution above more diagnostic than the city-wide median alone.
Most homes in Defiance were built after 1986, reducing the risk of lead contamination from plumbing. Older homes should still be tested.
Source: U.S. Census Bureau ACS B25034.
Defiance: Remediation Cost in Perspective
Equity impact data for Defiance lands in the favorable tier — remediation claims a small slice of what properties here are worth.
Remediation costs in Defiance are relatively low compared to home values. The $1,400–$4,900 estimated range is a small fraction of median property value. Home values are 214% above the Missouri average.
Protecting Children from Lead in Defiance
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.
Confirming what arrives at a specific faucet is something utility-side averages cannot do. With 37% of Defiance stock built before the lead-solder ban and citywide monitoring at or beyond the regulatory mark, a tap-level kit fits the standard diligence picture.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
Climate-Related Water Risk for Defiance
How does Defiance's flood record connect to local water quality? The NFIP documents 12 claims — enough to signal recurring events — and 100% of ZIP codes carry FEMA flood zone status. That combination places flooding in the category of factors that can periodically affect water infrastructure, even if the area isn't among the highest-exposure communities in the NFIP dataset.
Defiance has a moderate flood history with 12 FEMA claims averaging $12,286 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>$2,700</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 Defiance
- 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. Filters rated for Gross Beta can reduce the most common contaminant found in Defiance's water.
- Check your home's plumbing. With 37% of homes built before 1986, lead solder is a real possibility.
- Review your water system's CCR. Your utility publishes an annual Consumer Confidence Report with detailed test results. Request it or find it online.
Deep Dive Reports
Detailed analysis for Defiance, MO