Johnston, IA: 3 Violations — 59/100 (2026)
1 ZIP code · 6 water systems · Updated 2026-06-03
In recent monitoring cycles, Johnston tap water shows a mixed record for IA — several systems have documented violations alongside areas with clean compliance histories.
How Johnston Compares
Data: EPA SDWIS Last verified: 2026-06-03
Key Facts for Johnston Residents
- Your city's water systems recorded 3 violations in the past 5 years.
- Average lead level: 0.0016 mg/L.
- Homes built before 1986: 17% — older plumbing may contain lead solder.
- Estimated remediation: $3,000 per household.
- CDC health risk index: 11.97.
Johnston's Water Providers
3 independent water providers serve Johnston, IA — 6 systems appear in federal records.
Overview
We track water quality and home safety data for 1 ZIP code in Johnston, Iowa (population ~24,388), covering 6 community water systems serving approximately 345,145 people region-wide.
1 of 1 ZIP code (100%) have recorded EPA violations. All violations are monitoring/reporting type.
Home Safety Score
Average Home Safety Score for Johnston: C (59/100)
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
Johnston water systems draw from: Groundwater, Surface water.
Lead & Copper
- Average lead level (90th percentile): 0.0016 mg/L (EPA action level: 0.015 mg/L)
- 0 ZIP codes exceed the EPA lead action level
Radon Risk
Dominant radon zone: Zone 1 (High Risk)
The EPA recommends testing homes in Zone 1 and Zone 2 areas for radon.
Top Contaminants
| Contaminant | Category | Violations | ZIPs Affected |
|---|---|---|---|
| Contaminant 1003 | Other | 2 | 1 |
| Contaminant 1032 | Other | 2 | 1 |
| Contaminant 1052 | Other | 2 | 1 |
Areas with Most Violations
| ZIP Code | Safety Score | Violations | Health-Based | System |
|---|---|---|---|---|
| 50131 | C | 3 | 0 | Johnston Municipal Water Supply |
All ZIP Codes in Johnston
- 50131 [C] — 3 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.
Johnston Community Health Snapshot
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
What's in Johnston's Water?
Based on EPA violation records. Check your ZIP code report for system-specific contaminant data.
Johnston Infrastructure Age
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
Compared to many older metro areas, Johnston carries a relatively newer housing profile — the median build year of 2006 places most of the stock in the post-1986 era when lead solder was federally banned from new plumbing. That shift meaningfully reduces the baseline likelihood of lead leaching from copper joint solder. Homes from before 1986 do still exist in the mix, however, and individual testing remains the only way to confirm what a specific tap actually delivers.
Most homes in Johnston 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.
How Remediation Costs Compare in Johnston
While no remediation project is entirely without cost, the relationship between estimated remediation and property values in Johnston is notably favorable — the equity share is small enough that the household financial perspective is one of proportionality rather than pressure, and most homeowners can treat it as routine planning rather than a significant financial event.
Remediation costs in Johnston are relatively low compared to home values. The $2,000–$4,000 estimated range is a small fraction of median property value. Home values are 111% above the Iowa average.
Johnston: Lead Risk & Vulnerable Populations
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.
Reading Johnston's aggregate samples next to its housing-age figures yields a quiet baseline. Lead rests under the federal action benchmark in citywide monitoring, and only 17% of homes were built before the federal ban on solder containing lead. Households with kids — the population for whom CDC guidance places particular weight on minimizing exposure — can confirm in-home conditions with a draw-test kit, with a certified lead-removal filter available through certified retail channels if results warrant it.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
Johnston: Flood History & Water Damage Risk
The National Flood Insurance Program captures decades of claims at the local level, building a record of cumulative community flood exposure. For Johnston, that record documents 26 claims and 100% of ZIP codes inside FEMA-designated flood zones. What makes those numbers relevant to water quality is the set of mechanisms flooding activates: heavy precipitation that floods treatment intake zones can introduce contaminants upstream of normal filtration; well casings in low-lying areas can be infiltrated by floodwaters carrying bacteria, sediment, and chemical residue; and distribution system pressure changes during flooding can create backflow conditions. These effects become more probable as flood frequency and magnitude increase — and the NFIP record indicates both are meaningful factors locally.
Johnston has a moderate flood history with 26 FEMA claims averaging $37,163 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>$3,000</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 Johnston
- 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 Contaminant 1003 can reduce the most common contaminant found in Johnston's water.
- Check your home's plumbing. Homes built before 1986 may have lead solder in pipes. A licensed plumber can assess your risk.
Deep Dive Reports
Detailed analysis for Johnston, IA