Johnson County Water Quality: 41 Violations (KS)
9 water systems · 33 ZIP codes · Home Safety Score 66/100 (C) · 32 of 45 tracked ZIP records scored · Updated
Data: EPA Safe Drinking Water Information System (SDWIS), EPA ECHO Last verified:
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Find the Right Filter →Water Quality Overview
Johnson County has 9 community water systems across 33 directly mapped ZIP records. The systems report serving approximately 687,952 people. The available records contain 41 EPA violations, including 5 health-based violations.
Health-based violations account for 12% of all violations in Johnson County. These violations indicate contaminant levels that may pose direct risks to human health.
Violation Breakdown
| Violation Type | Count | Percentage |
|---|---|---|
| Health-based | 5 | 12.2% |
| Monitoring/Reporting | 36 | 87.8% |
| Total | 41 | 100% |
Health-based violations indicate contaminant levels exceeding EPA Maximum Contaminant Levels (MCLs). Monitoring violations indicate failures to test or report.
Cities with Most Violations
| Rank | City | Violations | Health-Based | ZIP Codes | Population |
|---|---|---|---|---|---|
| 1 | Olathe | 8 | 0 | 2 | 145,304 |
| 2 | Lenexa | 8 | 0 | 4 | 56,764 |
| 3 | Edgerton | 7 | 1 | 1 | 2,792 |
| 4 | De Soto | 6 | 3 | 1 | 6,537 |
| 5 | Gardner | 4 | 0 | 1 | 25,964 |
| 6 | Spring Hill | 4 | 1 | 1 | 12,832 |
| 7 | New Century | 4 | 0 | 1 | 651 |
Most Common Contaminants
| Contaminant | Category | Violations | ZIPs Affected | Health-Based |
|---|---|---|---|---|
| Lead and Copper Rule | Treatment Technique | 14 | 8 | No |
| Chlorite | Disinfection Byproducts | 6 | 6 | No |
| E. coli | Microbiological | 4 | 2 | No |
| Fecal Coliform | Microbiological | 2 | 2 | Yes |
| Total Trihalomethanes (TTHM) | Disinfection Byproducts | 2 | 2 | No |
| Haloacetic Acids (HAA5) | Disinfection Byproducts | 2 | 2 | No |
| Stage 2 DBP Rule | Treatment Technique | 2 | 2 | No |
Water Data and the Home Safety Score
This page reports EPA water-system facts without converting the broader Home Safety Score into a drinking-water grade. The county Home Safety grade (C) is a separate multi-source index that also requires PFAS screening, radon, and annual air-quality evidence. Check each ZIP report for the versioned score and its component coverage.
Water Systems in Johnson County
Johnson County is served by 9 community water systems, averaging 0.2 systems per ZIP code. Each system is independently regulated and tested by the EPA. Larger systems serving more people typically have more extensive monitoring requirements.
Water systems in Johnson County source water from a mix of surface water (rivers, reservoirs) and groundwater (wells, aquifers). Source type affects which contaminants are most likely to be detected.
How to Check Your Water in Johnson County
Enter your ZIP code on ZipCheckup for detailed water-system data including contaminant levels and violation history; the Home Safety Score is shown separately with its model version
Request your CCR — every water utility must provide an annual Consumer Confidence Report
Get a home test — certified kits ($20-$50) or professional lab tests ($150-$400) can detect contaminants not covered by routine testing
Consider filtration — NSF-certified filters can address specific contaminants found in your area
Check for lead — homes built before 1986 should test for lead regardless of utility compliance
EPA Enforcement
The EPA and state regulators have taken 147 enforcement actions against water systems in Johnson County. Enforcement actions range from compliance assistance and administrative orders to formal penalties. Systems under enforcement are required to remediate violations and may face ongoing monitoring requirements.
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Enforcement: EPA ECHO
Source publication schedules vary. See the page source and verification fields for available timing evidence.
Water Quality by ZIP Code in Johnson County
Water quality varies across Johnson County's 33 ZIP codes. Check your specific ZIP for detailed contaminant data.
| ZIP Code | City | Violations | Health | |
|---|---|---|---|---|
| 66021 | Edgerton | 7 | 1 | View → |
| 66018 | De Soto | 6 | 3 | View → |
| 66030 | Gardner | 4 | 0 | View → |
| 66031 | New Century | 4 | 0 | View → |
| 66061 | Olathe | 4 | 0 | View → |
| 66062 | Olathe | 4 | 0 | View → |
| 66083 | Spring Hill | 4 | 1 | View → |
| 66215 | Lenexa | 4 | 0 | View → |
| 66219 | Lenexa | 4 | 0 | View → |
| 66085 | Stilwell | 0 | 0 | View → |
| 66202 | Mission | 0 | 0 | View → |
| 66203 | Shawnee | 0 | 0 | View → |
| 66204 | Overland Park | 0 | 0 | View → |
| 66205 | Mission | 0 | 0 | View → |
| 66206 | Leawood | 0 | 0 | View → |
| 66207 | Overland Park | 0 | 0 | View → |
| 66208 | Prairie Village | 0 | 0 | View → |
| 66209 | Leawood | 0 | 0 | View → |
| 66210 | Overland Park | 0 | 0 | View → |
| 66211 | Leawood | 0 | 0 | View → |
Water facts and the Home Safety Score
The score shown here is the broader Home Safety Score, not a water-quality grade. Model 4.0.0 combines EPA SDWIS identity plus accepted ECHO SDWA lifecycle-based water compliance, PFAS screening, radon zones, and annual air-quality evidence. Johnson County has a score of 66/100 (Grade C) across 32 scored of 45 tracked ZIP records.
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Find the Right Filter →Frequently Asked Questions
Is the tap water safe in Johnson County, Kansas?
Johnson County has 9 community water systems with 41 recorded EPA violations, including 5 health-based. Water quality varies by ZIP code - check your specific location for detailed results.
How many water violations does Johnson County have?
Johnson County has 41 total EPA violations across 33 directly mapped ZIP records. 5 are health-based.
Which city in Johnson County has the most water violations?
Olathe has the most violations in Johnson County with 8 recorded EPA violations across 2 ZIP codes.
What contaminants are found in Johnson County water?
Johnson County water systems are monitored for over 90 EPA-regulated contaminants including lead, copper, nitrates, disinfection byproducts, and bacteria. Check your ZIP code for contaminant-specific data.
How can I test my water in Johnson County?
Contact your local water utility for free or low-cost testing. You can also use a certified home test kit ($20-$50) or hire a certified lab ($150-$400).