Decatur County, Iowa
7 ZIP codes · Avg score 50/100 · Grade D · Updated 2026-06-03
For households across Decatur County's 7 ZIP codes, below-average water safety data and recurring health violations make local monitoring worthwhile — checking the specific system serving an address is the most actionable starting point.
How Decatur County Compares
How Decatur County Compares
Decatur County scores 9 points below the Iowa state average (59/100) and 18 points below the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-03
ZIP Code Risk Map
Water Quality Map: Decatur County, Iowa
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Key Risk Factors
Health risk index: 14.1 (asthma 10.2%, diabetes 12.4%)
Estimated additional annual cost per homeowner: $616, driven primarily by energy_code_gap
Infrastructure: 0.431% avg pipe failure probability, 57% of ZIPs at high risk
67.9% of homes built before 1978 (lead paint era)
Violation History (2021–2025)
↓ Improving trendEPA violation counts by year across Decatur County water systems. Health-based shown in red, total in blue.
Peak year: 2022 with 12 violations. Past 5 years: 24 total (24 health-based). Health-based violations are declining versus the prior 2-year window.
Source: EPA SDWIS historical violations. Data may lag 6–12 months for the most recent year.
County Health Indicators vs National Average
Black markers indicate national averages. Source: CDC PLACES, Census ACS.
Infrastructure Overview
Sources: Census ACS (housing age), EPA SDWIS (infrastructure risk model), state bridge inspection data.
Compound Risk Breakdown
Estimated additional annual cost per homeowner: $616
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
3,484 housing units in Decatur County
Source: U.S. Census Bureau ACS B25034 (Year Structure Built).
Water Safety Affordability
How much it costs to fix water issues relative to home values in Decatur County
Remediation costs are relatively manageable for most homeowners in Decatur County, representing a small fraction of property value.
Remediation includes water filtration, lead abatement, radon mitigation, and flood protection where applicable. Source: Census ACS, EPA SDWIS.
Health Outcomes vs National Average
CDC PLACES data for Decatur County residents
Black markers = national averages. Red = above national avg. Green = below. Source: CDC PLACES, Census ACS.
Water Systems with Most Violations
Top 4 systems in Decatur County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | LAMONI MUNICIPAL UTILITIES | 2,104 | 9 |
| 2 | LEON WATER SUPPLY | 1,830 | 6 |
| 3 | Rathbun Regional Water Assn (rathbun) | 33,000 | 6 |
| 4 | Garden Grove Water Supply | 179 | 0 |
All ZIP Codes in Decatur County
7 ZIP codes tracked in Decatur County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 50103 | Garden Grove | 66 | C | 0 | $90K |
| 2 | 50140 | Lamoni | 65 | C | 9 (2 health) | $120K |
| 3 | 50144 | Leon | 60 | C | 6 (5 health) | $122K |
| 4 | 50065 | Davis City | 40 | D | 0 | $76K |
| 5 | 50067 | Decatur | 40 | D | 0 | $112K |
| 6 | 50262 | Van Wert | 40 | D | 0 | $77K |
| 7 | 50264 | Weldon | 40 | D | 0 | — |
Recommended Buyer Guides for Decatur County
Editorial-only picks, screened against the EPA detections on file.
- Best Lead Paint Test Kits — 67.9% of homes built before 1978
- Best Under-Sink Reverse Osmosis Systems — Multi-contaminant removal at the kitchen tap
- Best Radon Test Kits — EPA Radon Zone 1 (highest risk) dominant in county
Deep Dive Reports
Detailed analysis for Decatur County, Iowa
Overview
Decatur County in Iowa covers 7 ZIP codes with an average Home Safety Score of D (50/100).
2 of 7 ZIP codes have recorded EPA violations. 7 health-based violations have been documented.
← Back to Iowa water quality report
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Home values: U.S. Census Bureau ACS (median estimates by ZCTA)
Updated daily.
What You Can Do
Decatur County has a grade of D. Here are steps to protect your household.
Test your tap water
Order a certified lab test kit ($20-$50) to check for lead, bacteria, and other contaminants specific to your ZIP code.
Consider a certified water filter
NSF-certified filters can remove most common contaminants. Match the filter to your test results for best protection. Try our filter matcher
Contact your water utility
Request the latest Consumer Confidence Report (CCR) from your water provider. It details exactly what was found in your water supply.
Check for lead in your home
67.9% of homes in this county were built before 1978. Older plumbing and solder can leach lead into drinking water, especially in the morning.