Lyon County, Iowa
8 ZIP codes · Avg score 65/100 · Grade C · Updated 2026-06-03
Water monitoring across Lyon County's 8 ZIP codes paints a mid-range picture — solid compliance in some zones, documented concerns in others; most violations on record are concentrated in specific prior years rather than spread evenly across the full compliance history, and the overall county grade has held steady in the middle tier without major shifts in either direction.
How Lyon County Compares
How Lyon County Compares
Lyon County scores 6 points above the Iowa state average (59/100) and 3 points below the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-03
ZIP Code Risk Map
Water Quality Map: Lyon County, Iowa
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Key Risk Factors
Health risk index: 14.2 (asthma 10.3%, diabetes 11.8%)
Estimated additional annual cost per homeowner: $826, driven primarily by flood
Infrastructure: 0.455% avg pipe failure probability, 88% of ZIPs at high risk
72.4% of homes built before 1978 (lead paint era)
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: $826
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
4,873 housing units in Lyon 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 Lyon County
Remediation costs are relatively manageable for most homeowners in Lyon 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 Lyon County residents
Black markers = national averages. Red = above national avg. Green = below. Source: CDC PLACES, Census ACS.
Water Systems with Most Violations
Top 5 systems in Lyon County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | Lyon-sioux Rws-rock Rapids | 1,187 | 3 |
| 2 | Rock Rapids Municipal Water Works | 2,611 | 1 |
| 3 | Lyon-sioux Rws-doon | 1,765 | 1 |
| 4 | Doon Water Supply | 619 | 1 |
| 5 | Inwood Water Supply | 928 | 1 |
12 total water systems serve Lyon County.
All ZIP Codes in Lyon County
8 ZIP codes tracked in Lyon County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 51237 | George | 70 | B | 0 | $131K |
| 2 | 51242 | Lester | 70 | B | 0 | $185K |
| 3 | 51230 | Alvord | 66 | C | 0 | $190K |
| 4 | 51235 | Doon | 66 | C | 1 | $251K |
| 5 | 51240 | Inwood | 66 | C | 1 | $194K |
| 6 | 51241 | Larchwood | 64 | C | 1 | $270K |
| 7 | 51243 | Little Rock | 60 | C | 0 | $88K |
| 8 | 51246 | Rock Rapids | 60 | C | 0 | $233K |
Recommended Buyer Guides for Lyon County
Methodologically, the recommendation order reflects severity in the federal record: contaminants flagged in EPA detection records for this county outrank generic water concerns, FEMA-confirmed hazard ratings shift emergency-related categories upward, and CDC lead-exposure markers govern when lead-test kits and certified filters appear at the top of the list.
- Best Lead Paint Test Kits — 72.4% of homes built before 1978
- Best Radon Test Kits — EPA Radon Zone 1 (highest risk) dominant in county
- Best Sump Pumps — Flood is the top compound risk factor
- Best Mold Test Kits — Flood-driven moisture and mold risk
Deep Dive Reports
Detailed analysis for Lyon County, Iowa
Overview
Lyon County in Iowa covers 8 ZIP codes with an average Home Safety Score of C (65/100).
3 of 8 ZIP codes have recorded EPA violations. All violations are monitoring/reporting type.
← 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.