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Not health advice. Contact your local water utility for concerns.
Data from EPA Water Quality Reports. For official information, contact your water utility or health department.
Water quality data for 7 cities serving 542,221 residents
Johnson County in Kansas has an average water quality score of 73/100 (Grade B-) based on analysis of 7 municipal water systems. The county's water systems serve approximately 542,221 residents.
Water quality in Johnson County is fair, with some cities showing room for improvement. 2 cities have scores below 70, indicating elevated contaminant levels that residents should be aware of. Overland Park has the best water quality at 91/100.
7 cities ranked by water quality score
| Rank | City | Score | Grade | Population |
|---|---|---|---|---|
| 1 | Overland Park Top concern: Fluoride (13.2% of limit) | 91 | A | 201,260 |
| 2 | Olathe Top concern: Total Trihalomethanes (43.8% of limit) | 84 | B+ | 143,182 |
| 3 | Gardner Top concern: Copper (33.6% of limit) | 80 | B+ | 27,524 |
| 4 | Prairie Village Top concern: Haloacetic Acids (32.6% of limit) | 73 | B- | 17,386 |
| 5 | Leawood Top concern: Lead (29.9% of limit) | 70 | B- | 31,867 |
| 6 | Shawnee Top concern: Haloacetic Acids (57.3% of limit) | 64 | C | 64,430 |
| 7 | Lenexa Top concern: Total Trihalomethanes (55.8% of limit) | 48 | F | 56,572 |
Top detected contaminants across county water systems
| Contaminant | Avg Level | Max Level | EPA Limit | % of Limit | Cities |
|---|---|---|---|---|---|
| Haloacetic Acids | 18.194 ug/L | 34.366 ug/L | 60 ug/L | 30.3% | 7 |
| Total Trihalomethanes | 23.353 ug/L | 44.617 ug/L | 80 ug/L | 29.2% | 6 |
| Copper | 0.334 mg/L | 0.437 mg/L | 1.3 mg/L | 25.7% | 6 |
| Nitrite | 0.254 mg/L | 0.372 mg/L | 1 mg/L | 25.4% | 7 |
| Chromium | 0.021 mg/L | 0.05 mg/L | 0.1 mg/L | 21.5% | 7 |
| Fluoride | 0.79 mg/L | 1.15 mg/L | 4 mg/L | 19.7% | 6 |
| Lead | 0.003 mg/L | 0.005 mg/L | 0.015 mg/L | 19.3% | 6 |
| Nitrate | 1.86 mg/L | 3.762 mg/L | 10 mg/L | 18.6% | 7 |
Recent violations across county water systems
Showing 10 of 16 recent violations
Water quality in Johnson County, Kansas reflects the region's unique combination of water sources, treatment infrastructure, and environmental factors. Our comprehensive analysis examines 7 municipal water systems serving a combined population of over 542,221 residents.
The county shows moderate water quality performance, with scores ranging from 48/100 in Lenexa to 91/100 in Overland Park. This 43-point spread indicates significant variation in water quality across the county, suggesting different water sources or treatment approaches.
The most prevalent contaminants detected across Johnson County water systems include Haloacetic Acids, Total Trihalomethanes, Copper. All monitored contaminants remain within acceptable levels relative to EPA Maximum Contaminant Levels (MCLs).
Water quality in Johnson County is fair but shows room for improvement. Residents in cities scoring below 70 should consider water filtration, particularly for drinking and cooking. Check your specific city's report above for personalized recommendations.
Johnson County has an average water quality score of 73/100 (Grade B-) based on analysis of 7 municipal water systems serving 542,221 residents.
Overland Park has the highest water quality score in Johnson County at 91/100. View the detailed report for Overland Park.
Given the water quality variation across Johnson County, we recommend reviewing your specific city's water quality report. 2 cities have scores below 70, where filtration is particularly recommended.
Click on any city in the rankings table above to view its detailed water quality report, including contaminant levels, EPA compliance history, and filter recommendations.