Iowa Water Quality Report: 2,974 Violations Across 1,058 ZIPs
1,827 water systems · 1,058 ZIP codes · 2,974 violations · Updated 2026-06-11
Data: EPA Safe Drinking Water Information System (SDWIS), EPA ECHO Last verified: 2026-06-11
ZipCheckup tracks EPA drinking-water compliance for 1,827 public water systems serving 1,058 ZIP codes in Iowa. The state record shows 2,974 EPA violations, 159 health-based.
City Water Quality Map: Iowa
Each circle represents a city. Size indicates population, color indicates water quality grade. Tap a circle for details.
Violation Trend
EPA violations across all water systems in Iowa.
Cities with Most Violations in Iowa
| # | City | Grade | Violations | Systems | Population | |
|---|---|---|---|---|---|---|
| 1 | Cedar Rapids | C | 1,078 | 12 | 145,119 | Details → |
| 2 | Des Moines | C | 348 | 10 | 220,294 | Details → |
| 3 | Monticello | C | 119 | 3 | 6,384 | Details → |
| 4 | Davenport | D | 90 | 7 | 103,543 | Details → |
| 5 | Iowa City | D | 84 | 9 | 85,167 | Details → |
| 6 | Toddville | C | 55 | 5 | 1,372 | Details → |
| 7 | Fort Dodge | F | 27 | 7 | 28,633 | Details → |
| 8 | Marshalltown | D | 24 | 5 | 31,163 | Details → |
| 9 | Grinnell | F | 24 | 5 | 11,776 | Details → |
| 10 | Oxford | C | 22 | 7 | 1,997 | Details → |
Most Common Contaminants in Iowa
| Contaminant | Category | Violations | ZIPs Affected | Health Risk |
|---|---|---|---|---|
| Lead and Copper Rule | Treatment Technique | 539 | 138 | No |
| Copper | Inorganic | 271 | 73 | Yes |
| Surface Water Treatment Rule | Treatment Technique | 270 | 102 | No |
| Stage 1 DBP Rule | Treatment Technique | 223 | 100 | No |
| Haloacetic Acids (HAA5) | Disinfection Byproducts | 205 | 157 | Yes |
| Lead | Inorganic | 173 | 78 | Yes |
| Total Trihalomethanes (TTHM) | Disinfection Byproducts | 141 | 120 | Yes |
| Contaminant 1032 | Other | 50 | 44 | No |
| Contaminant 1052 | Other | 48 | 48 | No |
| Contaminant 1003 | Other | 39 | 38 | No |
Water Quality Overview
Iowa has 1,827 community water systems serving approximately 3,215,715 people across 1,058 ZIP codes. These systems have accumulated 2,974 EPA violations, including 159 health-based violations.
Health-based violations account for 5% of all violations in Iowa. These violations indicate contaminant levels that may pose direct risks to human health, as opposed to monitoring or reporting failures.
Violation Breakdown
| Violation Type | Count | Percentage |
|---|---|---|
| Health-based | 159 | 5.3% |
| Monitoring/Reporting | 2,815 | 94.7% |
| Total | 2,974 | 100% |
Health-based violations indicate contaminant levels exceeding EPA Maximum Contaminant Levels (MCLs). Monitoring violations indicate failures to test or report — these do not necessarily mean unsafe water, but they mean the water was not properly verified.
Cities with Most Violations
The following cities in Iowa have the highest number of EPA violations:
| Rank | City | Grade | Violations | Water Systems | Population |
|---|---|---|---|---|---|
| 1 | Cedar Rapids | C | 1,078 | 12 | 145,119 |
| 2 | Des Moines | C | 348 | 10 | 220,294 |
| 3 | Monticello | C | 119 | 3 | 6,384 |
| 4 | Davenport | D | 90 | 7 | 103,543 |
| 5 | Iowa City | D | 84 | 9 | 85,167 |
| 6 | Toddville | C | 55 | 5 | 1,372 |
| 7 | Fort Dodge | F | 27 | 7 | 28,633 |
| 8 | Marshalltown | D | 24 | 5 | 31,163 |
| 9 | Grinnell | F | 24 | 5 | 11,776 |
| 10 | Oxford | C | 22 | 7 | 1,997 |
Violation counts are cumulative across all water systems serving each city. Higher counts may reflect larger systems with more monitoring requirements, not necessarily worse water quality.
Violation Trend Over Time
Year-by-year EPA violations recorded across all water systems in Iowa:
| Year | Total Violations | Health-Based |
|---|---|---|
| 2021 | 31 | 31 |
| 2022 | 42 | 42 |
| 2023 | 54 | 54 |
| 2024 | 46 | 46 |
| 2025 | 22 | 22 |
Violations have decreased from 31 in 2021 to 22 in 2025, suggesting improving compliance across Iowa.
Most Common Contaminants
The following contaminants have caused the most violations across Iowa water systems:
| Contaminant | Category | Violations | ZIPs Affected | Health-Based |
|---|---|---|---|---|
| Lead and Copper Rule | Treatment Technique | 539 | 138 | No |
| Copper | Inorganic | 271 | 73 | Yes |
| Surface Water Treatment Rule | Treatment Technique | 270 | 102 | No |
| Stage 1 DBP Rule | Treatment Technique | 223 | 100 | No |
| Haloacetic Acids (HAA5) | Disinfection Byproducts | 205 | 157 | Yes |
| Lead | Inorganic | 173 | 78 | Yes |
| Total Trihalomethanes (TTHM) | Disinfection Byproducts | 141 | 120 | Yes |
| Barium | Inorganic | 34 | 8 | Yes |
| Total Coliform | Microbiological | 24 | 23 | No |
| Chlorine residual | Disinfectant | 16 | 16 | Yes |
How to Check Your Water in Iowa
Enter your ZIP code on ZipCheckup for detailed water system data including contaminant levels, violation history, and safety scores
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)
Consider filtration — NSF-certified filters can address specific contaminants found in your area
EPA Enforcement
The EPA and state regulators have taken 4,014 enforcement actions against water systems in Iowa. Enforcement actions range from compliance assistance to formal orders and penalties.
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Enforcement: EPA ECHO
Updated daily.
What are EPA violations?
Health-based violations mean a contaminant was detected above the EPA's Maximum Contaminant Level (MCL) - the legal limit designed to protect human health. Iowa has 159 such violations across its water systems. Not all violations cause illness, but repeated exceedances increase risk, especially for children and immunocompromised individuals.
Understanding water quality grades
ZipCheckup grades water systems from A to F based on EPA violation history, contaminant levels, and system compliance. Grade A means few or no violations; Grade F indicates persistent or serious issues. Grades are calculated per ZIP code and aggregated at the city, county, and state level.
Wondering about your tap water?
Water quality varies by ZIP code. Enter yours to see contaminant data, violations, and filtration recommendations specific to your area.
Check Your ZIP Code Water Quality →Frequently Asked Questions
Is the tap water safe to drink in Iowa?
Iowa has 1,827 community water systems with 2,974 recorded EPA violations, including 159 health-based. Water quality varies by city and ZIP code - check your specific location for detailed results.
How many water violations does Iowa have?
Iowa has 2,974 total EPA violations across 1,058 ZIP codes. 159 are health-based violations that indicate contaminant levels potentially harmful to human health. The remainder are monitoring or reporting violations.
Which city in Iowa has the worst water quality?
Cedar Rapids, IA has the most EPA violations among major cities in Iowa with 1078 recorded violations. Check individual ZIP codes for the most accurate picture of your local water quality.
Which city in Iowa has the best water quality?
Several cities in Iowa maintain excellent EPA compliance. Check individual city reports for details.
What contaminants are found in Iowa drinking water?
Iowa water systems are monitored for over 90 EPA-regulated contaminants including lead, copper, nitrates, disinfection byproducts, and bacteria. The most common violations vary by region - check your ZIP code for contaminant-specific data.