Johnson County, Iowa
13 ZIP codes · Avg score 64/100 · Grade C · Updated
ZipCheckup grade for Johnson County: C.
A mixed picture - some signals here are worth your attention.
Recent monitoring in Johnson County's 13 ZIP codes shows middle-tier safety - some systems are clean; others have logged EPA violations.
How Johnson County Compares
How Johnson County Compares
Johnson County scores 1 points above the Iowa state average (63/100) and 9 points below the national average (73/100).
Data: ZipCheckup Home Safety Score model 4.0.0; EPA SDWIS, UCMR 5, EPA radon zones, EPA AirData Last verified:
ZIP Code Risk Map
Water Quality Map: Johnson County, Iowa
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Key Risk Factors
Health risk index: 10.5 (asthma 9.8%, diabetes 8.8%)
Estimated additional annual cost per homeowner: $1,301, driven primarily by flood
46% of homes built before 1978 (lead paint era)
Violation History (2021–2024)
→ Stable trendEPA violation counts by year across Johnson County water systems. Health-based shown in red, total in blue.
Peak year: 2024 with 2 violations. Past 5 years: 3 total (3 health-based).
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
Modeled area-level indicator, not a failure probability. Sources: Census ACS housing age, EPA DWINS infrastructure needs, EPA SDWIS violations, and EPA lead indicators.
Compound Risk Breakdown
Estimated additional annual cost per homeowner: $1,301
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
64,226 housing units in Johnson 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 Johnson County
Remediation costs are relatively manageable for most homeowners in Johnson 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 Johnson County residents
Black markers = national averages. Red = above national avg. Green = below. Source: CDC PLACES, Census ACS.
Water systems serving Johnson County
8 community water systems serving Johnson County.
- C
- C
- C
- C
- C
- C
Show all 8 water systems
- C
- C
15 total water systems serve Johnson County.
Systems with the most violations in Johnson County
5 water systems with recorded EPA violations.
- C
- C
- C
- C
All ZIP Codes in Johnson County
13 ZIP codes tracked in Johnson County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 52241 | Coralville | 67 | C | 0 | $286K |
| 2 | 52242 | Iowa City | 67 | C | 0 | — |
| 3 | 52317 | North Liberty | 66 | C | 3 | $315K |
| 4 | 52246 | Iowa City | 63 | C | 8 | $327K |
| 5 | 52245 | Iowa City | 62 | C | 10 | $293K |
| 6 | 52240 | Iowa City | 57 | C | 20 | $241K |
| 7 | 52235 | Hills | — | — | $218K | |
| 8 | 52243 | Iowa City | — | — | — | |
| 9 | 52244 | Iowa City | — | — | — | |
| 10 | 52322 | Oxford | — | — | 0 | $249K |
| 11 | 52333 | Solon | — | — | 3 (1 health) | $348K |
| 12 | 52338 | Swisher | — | — | 4 (1 health) | $385K |
| 13 | 52340 | Tiffin | — | — | 0 | $318K |
Recommended Buyer Guides for Johnson County
While many sites publish identical guide lists across every county they cover, the selection here changes by location - driven by the EPA, NSF, FEMA, and CDC datasets that describe the actual conditions documented for this jurisdiction in the federal record.
- 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 Johnson County, Iowa
Overview
Johnson County in Iowa covers 13 tracked ZIP records with an average Home Safety Score of C (64/100) across 6 scored records.
6 of 10 ZIP codes with a reported violation count in the available EPA record have recorded EPA violations. 1 health-based violation appear in the available health breakdown.
← Back to Iowa Home Safety Profile
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- PFAS screening: EPA UCMR 5
- Radon zones: EPA Map of Radon Zones
- Air quality: EPA AirData annual AQI
- Home values: U.S. Census Bureau ACS (median estimates by ZCTA)
Reporting periods vary by source. Missing data is shown as unavailable, not as zero.