Knoxville, IA 50138
6 water systems • 14,923 residents
Excellent water quality with minimal contaminants
Score: 95/100
Graded on EPA violations, contaminants, severity, compliance, and enforcement history. See methodology.
Data updated June 2026 • Sources: EPA ECHO and EPA Envirofacts
6
Contaminants Detected
43
Violations on Record
6
Health-Based Violations
0
Recent Violations
Grade Breakdown
95 / 100 points
Recommended Water Filters
- ✓Point-of-Use Carbon Filter (NSF-certified for lead)
- ✓Ultraviolet (UV) Purification
Consult a water quality specialist for personalized recommendations.
Knoxville vs IA & National Average
Detected Contaminants
6 contaminants detected across water systems serving this ZIP code
| Contaminant | Category |
|---|---|
| Nitrite | Agricultural |
| Lead and Copper Rule | Heavy Metal |
| Coliform (TCR) | Microorganism |
| Revised Total Coliform Rule | Microorganism |
| Public Notice | Other |
| Combined Radium (-226 and -228) | Radiological |
Water System Information
- Systems Serving This ZIP:
- HILLOCK ESTATES, MARION CO. RURAL WATER DISTRICT, HARTFORD MHC LLC, WHEEL ESTATES MHC, VISTA VILLAGE MHC +1 more
- Population Served:
- 14,923
- Systems With Violations:
- 4 of 6
- Major Violations:
- 11
- Enforcement Actions:
- 43
Frequently Asked Questions
What does the grade mean?
Our A–F grade ranks this ZIP code's water quality against every other analyzed ZIP in the country, based on EPA data. A = among the best, F = among the most troubled.
Is my tap water safe to drink?
Water systems regulated by the EPA must comply with Safe Drinking Water Act standards. However, if you're concerned about water quality, consider a water filter appropriate for your contaminants.
How often is the data updated?
We update our data quarterly with the latest EPA ECHO and Envirofacts data. Historical violations are tracked to identify patterns.
What filters do you recommend?
Filter recommendations are based on detected contaminants in your area. See our Filter Guide for detailed information about different filter types.