Clayton County, Iowa
19 ZIP codes · Avg score 60/100 · Grade C · Updated 2026-06-03
Clayton County shows moderate water quality across its 19 ZIP codes — some areas carry violations worth monitoring.
How Clayton County Compares
How Clayton County Compares
Clayton County scores 1 points above the Iowa state average (59/100) and 8 points below the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-03
ZIP Code Risk Map
Water Quality Map: Clayton County, Iowa
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Key Risk Factors
Health risk index: 15.4 (asthma 10%, diabetes 13.7%)
Estimated additional annual cost per homeowner: $977, driven primarily by flood
Infrastructure: 0.445% avg pipe failure probability, 79% of ZIPs at high risk
73.3% 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: $977
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
11,284 housing units in Clayton 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 Clayton County
Remediation costs are relatively manageable for most homeowners in Clayton 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 Clayton 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 Clayton County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | Epworth Water Supply | 2,023 | 2 |
| 2 | Farley Water Supply | 1,766 | 2 |
| 3 | Holy Cross Water Supply | 356 | 2 |
| 4 | Volga Water Supply | 203 | 1 |
| 5 | Luana Water Works | 301 | 1 |
16 total water systems serve Clayton County.
All ZIP Codes in Clayton County
19 ZIP codes tracked in Clayton County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 52035 | Colesburg | 70 | B | 0 | $132K |
| 2 | 52042 | Edgewood | 70 | B | 0 | $230K |
| 3 | 52047 | Farmersburg | 70 | B | 0 | $101K |
| 4 | 52049 | Garnavillo | 70 | B | 0 | $168K |
| 5 | 52072 | Saint Olaf | 70 | B | 0 | $114K |
| 6 | 52076 | Strawberry Point | 66 | C | 0 | $140K |
| 7 | 52156 | Luana | 66 | C | 1 | $217K |
| 8 | 52159 | Monona | 66 | C | 0 | $149K |
| 9 | 52077 | Volga | 65 | C | 1 | $81K |
| 10 | 52158 | Marquette | 64 | C | 0 | $133K |
| 11 | 52052 | Guttenberg | 60 | C | 0 | $189K |
| 12 | 52053 | Holy Cross | 60 | C | 2 | $282K |
| 13 | 52043 | Elkader | 59 | C | 0 | $145K |
| 14 | 52048 | Garber | 53 | D | 0 | $82K |
| 15 | 52146 | Harpers Ferry | 53 | D | 0 | $215K |
| 16 | 52044 | Elkport | 45 | D | 0 | — |
| 17 | 52157 | Mc Gregor | 45 | D | 0 | $164K |
| 18 | 52038 | Dundee | 40 | D | 0 | $169K |
| 19 | 52050 | Greeley | 40 | D | 0 | $211K |
Recommended Buyer Guides for Clayton County
Where county records show a lead exceedance or pre-1978 housing concentration, lead-specific filters and test kits move toward the top of the list.
- Best Lead Paint Test Kits — 73.3% 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 Clayton County, Iowa
Overview
Clayton County in Iowa covers 19 ZIP codes with an average Home Safety Score of C (60/100).
3 of 19 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.