Johnston, IA: 1 Violation - Home Safety 66/100
1 ZIP code · 5 water systems · Updated
ZipCheckup grade for Johnston: C.
A mixed picture - some signals here are worth your attention.
Neither high nor low, the composite grade for Johnston, IA is a C, built from ZIP-level scores.
How Johnston Compares
Data: EPA SDWIS
Key Facts for Johnston Residents
- Water systems mapped to your city have 1 violation on record since 2021.
- Average of reported 90th-percentile lead results: 0.0014 mg/L.
- Homes built before 1986: 17% - older plumbing may contain lead solder.
- Health risk index (ZipCheckup composite of CDC data): 11.97.
Johnston's Water Providers
The 3 largest of 5 systems connected with Johnston, IA are listed below.
- C
- C
- C
Overview
We track home safety data for 1 ZIP code in Johnston, Iowa (population ~24,388), covering 5 community water systems serving approximately 347,226 people region-wide. The EPA snapshots used for this build directly map water systems to 1 of 1 ZIP codes.
1 of 1 ZIP code with a reported violation count in the available EPA record (100%) have recorded EPA violations. The available record reports no health-based violations for this measured scope.
Home Safety Score
Average Home Safety Score for Johnston: C (66/100)
Model 4.0.0 uses four measured components across three equally weighted domains. If a required domain is unavailable, no score is published:
| Factor | What It Measures |
|---|---|
| Water Quality | EPA violations and compliance history |
| PFAS MCL Screen | UCMR 5 testing against the covered federal MCLs |
| Radon Risk | EPA radon zone classification |
| Annual AQI | EPA AirData county-year median with at least 90 observed days |
Water Sources
Johnston water systems draw from: Groundwater, Surface water.
Lead & Copper
- Average of reported 90th-percentile lead results: 0.0014 mg/L (EPA action level: 0.015 mg/L)
- 0 of 1 ZIP code with known status exceed the EPA lead action level
Radon Risk
1 of 1 ZIP records with known zones is in EPA Radon Zone 1.
The EPA recommends testing all homes regardless of radon zone. County radon zones cannot replace an in-home radon test.
Top Contaminants
| Contaminant | Category | Violations | ZIPs Affected |
|---|---|---|---|
| Nitrite | Inorganic | 2 | 1 |
Areas with Most Violations
| ZIP Code | Safety Score | Violations | Health-Based | System |
|---|---|---|---|---|
| 50131 | C | 1 | 0 | Johnston Municipal Water Supply |
All ZIP Codes in Johnston
- 50131 [C] - 1 violation
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
Reporting periods vary by source. Missing data is shown as unavailable, not as zero.
Johnston Community Health Snapshot
Source: CDC PLACES (County-level estimates). County health indicators are shown for context only and are not linked to this area's water records.
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
Housing age is a rough starting point, not an answer. Johnston has a median build year of 2006, but any single home may be older or newer than that figure, may have had plumbing replaced, or may still have original fixtures. Lead can also come from a service line or older brass fittings, so a water test or a check of the utility's service line inventory says more about one address than the citywide build year does.
Most homes in Johnston were built after 1986; lead exposure at a tap still depends on its service line and plumbing. Older homes should still be tested.
Source: U.S. Census Bureau ACS B25034.
Johnston: Lead Risk & Vulnerable Populations
Why children are most at risk: The CDC states that no safe blood lead level in children has been identified. Children under 6 absorb lead more readily than adults, and even low levels can cause developmental delays, learning difficulties, and behavioral problems.
17% of the Johnston housing stock dates from before 1986, the year Congress limited lead in pipes, solder and flux. Water systems report lead as the 90th percentile of their tap samples, and the average of those results across the city's ZIP codes is below 0.010 mg/L. Because lead in drinking water usually comes from corrosion of a building's own service line and plumbing, that average cannot stand in for a single address.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
Johnston: NFIP Claim Records and Water-Quality Context
Historical NFIP data for Johnston contains 26 flood insurance claims. Among claims with payment data, the average reported building, contents, and ICC component sum is $43,920. Among ZIP codes with claim records, 100% have an A- or V-family dominant rated zone recorded in those historical claims. This is not a complete current FEMA property-map inventory.
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.
Claim count does not establish current property risk. Check the exact address in FEMA's current map and obtain a property-specific insurance quote when relevant.
Source: historical FEMA National Flood Insurance Program (NFIP) claim records. No current FEMA property-map designation is asserted.
What You Can Do in Johnston
- Test your water at home. City-level data shows averages - your tap may differ. Check the certification, price and turnaround time of any water test kit or lab service.
- Install a certified water filter. For Nitrite, listed in the water-quality records for Johnston: if it is a rule or reporting requirement rather than a contaminant, ask your utility what the record involved; for bacteria, follow any boil-water notice from your utility; for a specific chemical contaminant, check whether a filter is certified to reduce it. Not every contaminant has a consumer filter certification.
- 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